<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 5.10a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef roleURI="http://RCAT/role/Cover" xlink:href="rcat-20211031.xsd#Cover" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/BalanceSheets" xlink:href="rcat-20211031.xsd#BalanceSheets" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/BalanceSheetsParenthetical" xlink:href="rcat-20211031.xsd#BalanceSheetsParenthetical" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/StatementsOfOperations" xlink:href="rcat-20211031.xsd#StatementsOfOperations" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/CashFlowsStatements" xlink:href="rcat-20211031.xsd#CashFlowsStatements" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/StockholdersEquityStatements" xlink:href="rcat-20211031.xsd#StockholdersEquityStatements" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/StockholdersEquityStatementsParenthetical" xlink:href="rcat-20211031.xsd#StockholdersEquityStatementsParenthetical" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note1-Business" xlink:href="rcat-20211031.xsd#Note1-Business" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note2-SummaryOfSignificantAccountingPolicies" xlink:href="rcat-20211031.xsd#Note2-SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note3FairValueMeasurements" xlink:href="rcat-20211031.xsd#Note3FairValueMeasurements" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note4Inventories" xlink:href="rcat-20211031.xsd#Note4Inventories" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note5-OtherCurrentAssets" xlink:href="rcat-20211031.xsd#Note5-OtherCurrentAssets" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note6PropertyAndEquipment" xlink:href="rcat-20211031.xsd#Note6PropertyAndEquipment" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note7LeaseAgreements" xlink:href="rcat-20211031.xsd#Note7LeaseAgreements" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note8DebtObligations" xlink:href="rcat-20211031.xsd#Note8DebtObligations" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note9-DueToRelatedParty" xlink:href="rcat-20211031.xsd#Note9-DueToRelatedParty" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note10-ConvertibleNotes" xlink:href="rcat-20211031.xsd#Note10-ConvertibleNotes" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note11-IncomeTaxes" xlink:href="rcat-20211031.xsd#Note11-IncomeTaxes" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note12-CommonStock" xlink:href="rcat-20211031.xsd#Note12-CommonStock" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note13-PreferredStock" xlink:href="rcat-20211031.xsd#Note13-PreferredStock" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note14-Warrants" xlink:href="rcat-20211031.xsd#Note14-Warrants" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note15-ShareBasedAwards" xlink:href="rcat-20211031.xsd#Note15-ShareBasedAwards" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note16-Derivatives" xlink:href="rcat-20211031.xsd#Note16-Derivatives" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note17-Related-partyTransactions" xlink:href="rcat-20211031.xsd#Note17-Related-partyTransactions" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note18-SubsequentEvents" xlink:href="rcat-20211031.xsd#Note18-SubsequentEvents" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note2-SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="rcat-20211031.xsd#Note2-SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note1-BusinessTables" xlink:href="rcat-20211031.xsd#Note1-BusinessTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note3FairValueMeasurementsTables" xlink:href="rcat-20211031.xsd#Note3FairValueMeasurementsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note4InventoriesTables" xlink:href="rcat-20211031.xsd#Note4InventoriesTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note5-OtherCurrentAssetsTables" xlink:href="rcat-20211031.xsd#Note5-OtherCurrentAssetsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note6PropertyAndEquipmentTables" xlink:href="rcat-20211031.xsd#Note6PropertyAndEquipmentTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note7LeaseAgreementsTables" xlink:href="rcat-20211031.xsd#Note7LeaseAgreementsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note8DebtObligationsTables" xlink:href="rcat-20211031.xsd#Note8DebtObligationsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note14-WarrantsTables" xlink:href="rcat-20211031.xsd#Note14-WarrantsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note15-ShareBasedAwardsTables" xlink:href="rcat-20211031.xsd#Note15-ShareBasedAwardsTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note16-DerivativesTables" xlink:href="rcat-20211031.xsd#Note16-DerivativesTables" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note1-BusinessDetailsNarrative" xlink:href="rcat-20211031.xsd#Note1-BusinessDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/SummaryOfPurchasePriceAndItsRelatedAllocation" xlink:href="rcat-20211031.xsd#SummaryOfPurchasePriceAndItsRelatedAllocation" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/RevisedSummaryOfPurchasePriceAndItsRelatedAllocation" xlink:href="rcat-20211031.xsd#RevisedSummaryOfPurchasePriceAndItsRelatedAllocation" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note2-SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:href="rcat-20211031.xsd#Note2-SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/AmortizedCostNetUnrealizedGainsOrLossesAndFairValues" xlink:href="rcat-20211031.xsd#AmortizedCostNetUnrealizedGainsOrLossesAndFairValues" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/ContractualMaturities" xlink:href="rcat-20211031.xsd#ContractualMaturities" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/FairValueHierarchy" xlink:href="rcat-20211031.xsd#FairValueHierarchy" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/InventoriesDetails" xlink:href="rcat-20211031.xsd#InventoriesDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/OtherCurrentAssetsDetails" xlink:href="rcat-20211031.xsd#OtherCurrentAssetsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/PropertyAndEquipmentDetails" xlink:href="rcat-20211031.xsd#PropertyAndEquipmentDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/OperatingLeasesForRealEstateLocationsDetails" xlink:href="rcat-20211031.xsd#OperatingLeasesForRealEstateLocationsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/FutureLeasePaymentObligationsDetails" xlink:href="rcat-20211031.xsd#FutureLeasePaymentObligationsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note8DebtObligationsDetailsNarrative" xlink:href="rcat-20211031.xsd#Note8DebtObligationsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/AgreementsWithShopify" xlink:href="rcat-20211031.xsd#AgreementsWithShopify" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/OutstandingPrincipalPaymentsDetails" xlink:href="rcat-20211031.xsd#OutstandingPrincipalPaymentsDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note9-DueToRelatedPartyDetailsNarrative" xlink:href="rcat-20211031.xsd#Note9-DueToRelatedPartyDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note10-ConvertibleNotesDetailsNarrative" xlink:href="rcat-20211031.xsd#Note10-ConvertibleNotesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note11-IncomeTaxesDetailsNarrative" xlink:href="rcat-20211031.xsd#Note11-IncomeTaxesDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note12-CommonStockDetailsNarrative" xlink:href="rcat-20211031.xsd#Note12-CommonStockDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note13-PreferredStockDetailsNarrative" xlink:href="rcat-20211031.xsd#Note13-PreferredStockDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/ChangesInWarrantsOutstandingDetails" xlink:href="rcat-20211031.xsd#ChangesInWarrantsOutstandingDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note14-WarrantsDetailsNarrative" xlink:href="rcat-20211031.xsd#Note14-WarrantsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/AssumptionsUsedToCalculateFairValueOfOptionsGrantedDetails" xlink:href="rcat-20211031.xsd#AssumptionsUsedToCalculateFairValueOfOptionsGrantedDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note15-ShareBasedAwardsDetailsNarrative" xlink:href="rcat-20211031.xsd#Note15-ShareBasedAwardsDetailsNarrative" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/SummaryOfActivityUnderPlan" xlink:href="rcat-20211031.xsd#SummaryOfActivityUnderPlan" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/StockCompensationExpenseDetails" xlink:href="rcat-20211031.xsd#StockCompensationExpenseDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/AssumptionsUsedToDetermineFairValueOfDerivativeWarrantLiability" xlink:href="rcat-20211031.xsd#AssumptionsUsedToDetermineFairValueOfDerivativeWarrantLiability" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/ChangesInDerivativeLiabilityDetails" xlink:href="rcat-20211031.xsd#ChangesInDerivativeLiabilityDetails" xlink:type="simple" />
    <link:roleRef roleURI="http://RCAT/role/Note17-Related-partyTransactionsDetailsNarrative" xlink:href="rcat-20211031.xsd#Note17-Related-partyTransactionsDetailsNarrative" xlink:type="simple" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Cover" xlink:title="00000001 - Document - Cover" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/BalanceSheets" xlink:title="00000002 - Statement - Consolidated Balance Sheets (Unaudited)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/BalanceSheetsParenthetical" xlink:title="00000003 - Statement - Consolidated Balance Sheets (Unaudited) (Parenthetical)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesAPreferredStockMember" xlink:label="loc_us-gaapSeriesAPreferredStockMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesAPreferredStockMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember" xlink:label="loc_us-gaapSeriesBPreferredStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesBPreferredStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized_70" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding_70" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_70" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding_70" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/StatementsOfOperations" xlink:title="00000004 - Statement - Consolidated Statements Of Operations (Unaudited)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/CashFlowsStatements" xlink:title="00000005 - Statement - Condensed Consolidated Cash Flows Statements (Unaudited)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/StockholdersEquityStatements" xlink:title="00000006 - Statement - Consolidated Stockholders&apos; Equity Statements (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_SeriesAPreferredStock1Member" xlink:label="loc_RCATSeriesAPreferredStock1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_RCATSeriesAPreferredStock1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_SeriesBPreferredStock1Member" xlink:label="loc_RCATSeriesBPreferredStock1Member_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_RCATSeriesBPreferredStock1Member_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaapAdditionalPaidInCapitalMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAdditionalPaidInCapitalMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaapRetainedEarningsMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapRetainedEarningsMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaapAccumulatedOtherComprehensiveIncomeMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAccumulatedOtherComprehensiveIncomeMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquity_80" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaapSharesOutstanding_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesOutstanding_80" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensation_80" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLoss_80" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_StockIssuedDuringPeriodValueConversionOfDebt" xlink:label="loc_RCATStockIssuedDuringPeriodValueConversionOfDebt_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATStockIssuedDuringPeriodValueConversionOfDebt_80" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_StockIssuedDuringPeriodSharesConversionOfDebt" xlink:label="loc_RCATStockIssuedDuringPeriodSharesConversionOfDebt_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATStockIssuedDuringPeriodSharesConversionOfDebt_80" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueAcquisitions_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueAcquisitions_80" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_80" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueNewIssues_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueNewIssues_80" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesNewIssues_80" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromWarrantExercises" xlink:label="loc_us-gaapProceedsFromWarrantExercises_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapProceedsFromWarrantExercises_80" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_80" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueConversionOfConvertibleSecurities_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueConversionOfConvertibleSecurities_80" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_80" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_80" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueIssuedForServices_80" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_80" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaapOtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_80" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_StockIssuedDuringPeriodValueAcquisitions1" xlink:label="loc_RCATStockIssuedDuringPeriodValueAcquisitions1_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATStockIssuedDuringPeriodValueAcquisitions1_80" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_StockIssuedDuringPeriodSharesAcquisitions1" xlink:label="loc_RCATStockIssuedDuringPeriodSharesAcquisitions1_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATStockIssuedDuringPeriodSharesAcquisitions1_80" xlink:type="arc" order="22" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/StockholdersEquityStatementsParenthetical" xlink:title="00000007 - Statement - Consolidated Stockholders&apos; Equity Statements (Unaudited) (Parenthetical)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note1-Business" xlink:title="00000008 - Disclosure - Note 1 - The Business" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note2-SummaryOfSignificantAccountingPolicies" xlink:title="00000009 - Disclosure - Note 2 - Summary of Significant Accounting Policies" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note3FairValueMeasurements" xlink:title="00000010 - Disclosure - Note 3 &#8211; Fair Value Measurements" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note4Inventories" xlink:title="00000011 - Disclosure - Note 4 &#8211; Inventories" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note5-OtherCurrentAssets" xlink:title="00000012 - Disclosure - Note 5 - Other Current Assets" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note6PropertyAndEquipment" xlink:title="00000013 - Disclosure - Note 6 &#8211; Property and Equipment" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note7LeaseAgreements" xlink:title="00000014 - Disclosure - Note 7 &#8211; Lease Agreements" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note8DebtObligations" xlink:title="00000015 - Disclosure - Note 8 &#8211; Debt Obligations" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note9-DueToRelatedParty" xlink:title="00000016 - Disclosure - Note 9 - Due to Related Party" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note10-ConvertibleNotes" xlink:title="00000017 - Disclosure - Note 10 - Convertible Notes" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note11-IncomeTaxes" xlink:title="00000018 - Disclosure - Note 11 - Income Taxes" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note12-CommonStock" xlink:title="00000019 - Disclosure - Note 12 - Common Stock" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note13-PreferredStock" xlink:title="00000020 - Disclosure - Note 13 - Preferred Stock" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note14-Warrants" xlink:title="00000021 - Disclosure - Note 14 - Warrants" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note15-ShareBasedAwards" xlink:title="00000022 - Disclosure - Note 15 - Share Based Awards" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note16-Derivatives" xlink:title="00000023 - Disclosure - Note 16 - Derivatives" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note17-Related-partyTransactions" xlink:title="00000024 - Disclosure - Note 17 - Related-Party Transactions" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note18-SubsequentEvents" xlink:title="00000025 - Disclosure - Note 18 - Subsequent Events" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note2-SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="00000026 - Disclosure - Note 2 - Summary of Significant Accounting Policies (Policies)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note1-BusinessTables" xlink:title="00000027 - Disclosure - Note 1 - The Business (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note3FairValueMeasurementsTables" xlink:title="00000028 - Disclosure - Note 3 &#8211; Fair Value Measurements (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note4InventoriesTables" xlink:title="00000029 - Disclosure - Note 4 &#8211; Inventories (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note5-OtherCurrentAssetsTables" xlink:title="00000030 - Disclosure - Note 5 - Other Current Assets (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note6PropertyAndEquipmentTables" xlink:title="00000031 - Disclosure - Note 6 &#8211; Property and Equipment (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note7LeaseAgreementsTables" xlink:title="00000032 - Disclosure - Note 7 &#8211; Lease Agreements (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note8DebtObligationsTables" xlink:title="00000033 - Disclosure - Note 8 &#8211; Debt Obligations (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note14-WarrantsTables" xlink:title="00000034 - Disclosure - Note 14 - Warrants (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note15-ShareBasedAwardsTables" xlink:title="00000035 - Disclosure - Note 15 - Share Based Awards (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note16-DerivativesTables" xlink:title="00000036 - Disclosure - Note 16 - Derivatives (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note1-BusinessDetailsNarrative" xlink:title="00000037 - Disclosure - Note 1 - The Business (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaapRestructuringCostAndReserveLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaapScheduleOfRestructuringAndRelatedCostsTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_us-gaapScheduleOfRestructuringAndRelatedCostsTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfRestructuringAndRelatedCostsTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition2Member" xlink:label="loc_RCATBusinessAcquisition2Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition2Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition3Member" xlink:label="loc_RCATBusinessAcquisition3Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition3Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition4Member" xlink:label="loc_RCATBusinessAcquisition4Member_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition4Member_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ShareIssuanceValueMergerAgreement" xlink:label="loc_RCATShareIssuanceValueMergerAgreement_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATShareIssuanceValueMergerAgreement_60" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_VolumeWeightedAveragePriceMerger" xlink:label="loc_RCATVolumeWeightedAveragePriceMerger_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATVolumeWeightedAveragePriceMerger_60" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AggregateSharesIssuedMerger" xlink:label="loc_RCATAggregateSharesIssuedMerger_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAggregateSharesIssuedMerger_60" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ValueOfSharesIssuedMerger" xlink:label="loc_RCATValueOfSharesIssuedMerger_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATValueOfSharesIssuedMerger_60" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CommonStockClosingPriceOnDate" xlink:label="loc_RCATCommonStockClosingPriceOnDate_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATCommonStockClosingPriceOnDate_60" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedCustomerRelationshipsGross" xlink:label="loc_us-gaapFiniteLivedCustomerRelationshipsGross_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_us-gaapFiniteLivedCustomerRelationshipsGross_60" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AcquisitionTransactionValue" xlink:label="loc_RCATAcquisitionTransactionValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAcquisitionTransactionValue_60" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AcquisitionStockIssuedShares" xlink:label="loc_RCATAcquisitionStockIssuedShares_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAcquisitionStockIssuedShares_60" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AcquisitionStockIssuedValue" xlink:label="loc_RCATAcquisitionStockIssuedValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAcquisitionStockIssuedValue_60" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AcquisitionSecuredPromissoryNoteIssuedPrincipalAmount" xlink:label="loc_RCATAcquisitionSecuredPromissoryNoteIssuedPrincipalAmount_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAcquisitionSecuredPromissoryNoteIssuedPrincipalAmount_60" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AcquisitionCashPaymentMade" xlink:label="loc_RCATAcquisitionCashPaymentMade_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAcquisitionCashPaymentMade_60" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AcquisitionShareConsiderationAcquiredValue" xlink:label="loc_RCATAcquisitionShareConsiderationAcquiredValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATAcquisitionShareConsiderationAcquiredValue_60" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingCostsOfAcquireePaidForByCompanyPriorToAcquisitionClosing" xlink:label="loc_RCATOperatingCostsOfAcquireePaidForByCompanyPriorToAcquisitionClosing_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATOperatingCostsOfAcquireePaidForByCompanyPriorToAcquisitionClosing_60" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_WorkingCapitalDeficitMaximumAmountToResultInReductionOfShareConsiderationValue" xlink:label="loc_RCATWorkingCapitalDeficitMaximumAmountToResultInReductionOfShareConsiderationValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATWorkingCapitalDeficitMaximumAmountToResultInReductionOfShareConsiderationValue_60" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ReductionInPurchasePriceFromWorkingCapitalDeficitOfAquiree" xlink:label="loc_RCATReductionInPurchasePriceFromWorkingCapitalDeficitOfAquiree_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRestructuringCostAndReserveLineItems" xlink:to="loc_RCATReductionInPurchasePriceFromWorkingCapitalDeficitOfAquiree_60" xlink:type="arc" order="14" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/SummaryOfPurchasePriceAndItsRelatedAllocation" xlink:title="00000038 - Disclosure - summary of the purchase price and its related allocation">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaapBusinessAcquisitionLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaapScheduleOfBusinessAcquisitionsByAcquisitionTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition2Member" xlink:label="loc_RCATBusinessAcquisition2Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition2Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition3Member" xlink:label="loc_RCATBusinessAcquisition3Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition3Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" xlink:label="loc_us-gaapBusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessCombinationPromissoryNoteIssued" xlink:label="loc_RCATBusinessCombinationPromissoryNoteIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATBusinessCombinationPromissoryNoteIssued_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaapBusinessCombinationConsiderationTransferred1_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationConsiderationTransferred1_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AssetsAcquiredMergerAbstract" xlink:label="loc_RCATAssetsAcquiredMergerAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATAssetsAcquiredMergerAbstract_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_50" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_50" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBrandName" xlink:label="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBrandName_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBrandName_50" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCustomerRelationships" xlink:label="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCustomerRelationships_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCustomerRelationships_50" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_50" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_LiabilitiesAssumedMergerAbstract" xlink:label="loc_RCATLiabilitiesAssumedMergerAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATLiabilitiesAssumedMergerAbstract_50" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_50" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt_50" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_50" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_50" xlink:type="arc" order="16" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_50" xlink:type="arc" order="17" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_50" xlink:type="arc" order="18" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaapPaymentsToAcquireBusinessesGross_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapPaymentsToAcquireBusinessesGross_50" xlink:type="arc" order="19" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProprietaryTechnology" xlink:label="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProprietaryTechnology_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProprietaryTechnology_50" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonCompeteAgreement" xlink:label="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonCompeteAgreement_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonCompeteAgreement_50" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_50" xlink:type="arc" order="22" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/RevisedSummaryOfPurchasePriceAndItsRelatedAllocation" xlink:title="00000039 - Disclosure - revised summary of the purchase price and its related allocation">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaapBusinessAcquisitionLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaapScheduleOfBusinessAcquisitionsByAcquisitionTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaapBusinessAcquisitionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="loc_us-gaapBusinessAcquisitionAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapBusinessAcquisitionAxis" xlink:to="loc_us-gaapBusinessAcquisitionAcquireeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition4Member" xlink:label="loc_RCATBusinessAcquisition4Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition4Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessAcquisition5Member" xlink:label="loc_RCATBusinessAcquisition5Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionAcquireeDomain" xlink:to="loc_RCATBusinessAcquisition5Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" xlink:label="loc_us-gaapBusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaapPaymentsToAcquireBusinessesGross_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapPaymentsToAcquireBusinessesGross_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaapBusinessCombinationConsiderationTransferred1_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationConsiderationTransferred1_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AssetsAcquiredMergerAbstract" xlink:label="loc_RCATAssetsAcquiredMergerAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATAssetsAcquiredMergerAbstract_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_50" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_50" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_LiabilitiesAssumedMergerAbstract" xlink:label="loc_RCATLiabilitiesAssumedMergerAbstract_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATLiabilitiesAssumedMergerAbstract_50" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_50" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_50" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_50" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_50" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsOther" xlink:label="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsOther_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_RCATBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsOther_50" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_50" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt" xlink:label="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapBusinessAcquisitionLineItems" xlink:to="loc_us-gaapBusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt_50" xlink:type="arc" order="16" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note2-SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:title="00000040 - Disclosure - Note 2 - Summary of Significant Accounting Policies (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/AmortizedCostNetUnrealizedGainsOrLossesAndFairValues" xlink:title="00000041 - Disclosure - Amortized cost, net unrealized gains or losses, and fair values">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesChangeInFairValueAxis" xlink:label="loc_RCATAvailableForSaleSecuritiesChangeInFairValueAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_RCATAvailableForSaleSecuritiesChangeInFairValueAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesChangeInFairValueDomain" xlink:label="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueAxis" xlink:to="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesChangeInFairValueDomain" xlink:label="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueAxis" xlink:to="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesAmortizedCostMember" xlink:label="loc_RCATAvailableForSaleSecuritiesAmortizedCostMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesAmortizedCostMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesFairValueMember" xlink:label="loc_RCATAvailableForSaleSecuritiesFairValueMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesFairValueMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesUnrealizedGainLossMember" xlink:label="loc_RCATAvailableForSaleSecuritiesUnrealizedGainLossMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesUnrealizedGainLossMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AssetBackedSecuritiesNetUnrealizedGainLossesMember" xlink:label="loc_RCATAssetBackedSecuritiesNetUnrealizedGainLossesMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:to="loc_RCATAssetBackedSecuritiesNetUnrealizedGainLossesMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CorporateBondsUnrealizedGainLossesMember" xlink:label="loc_RCATCorporateBondsUnrealizedGainLossesMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:to="loc_RCATCorporateBondsUnrealizedGainLossesMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesNetUnrealizedGainLossesMember" xlink:label="loc_RCATAvailableForSaleSecuritiesNetUnrealizedGainLossesMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesChangeInFairValueDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesNetUnrealizedGainLossesMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsAtCarryingValue" xlink:label="loc_us-gaapMoneyMarketFundsAtCarryingValue_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapMoneyMarketFundsAtCarryingValue_70" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss" xlink:label="loc_us-gaapDebtSecuritiesAvailableForSaleUnrealizedGainLoss_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapDebtSecuritiesAvailableForSaleUnrealizedGainLoss_70" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetBackedSecuritiesAtCarryingValue" xlink:label="loc_us-gaapAssetBackedSecuritiesAtCarryingValue_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAssetBackedSecuritiesAtCarryingValue_70" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CorporateBondsAtCarryingValue" xlink:label="loc_RCATCorporateBondsAtCarryingValue_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATCorporateBondsAtCarryingValue_70" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaapAvailableForSaleSecurities_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAvailableForSaleSecurities_70" xlink:type="arc" order="4" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/ContractualMaturities" xlink:title="00000042 - Disclosure - Contractual Maturities">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesContractualMaturitiesAxis" xlink:label="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:label="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesAxis" xlink:to="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:label="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesAxis" xlink:to="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ContractualMaturitiesPeriod1Member" xlink:label="loc_RCATContractualMaturitiesPeriod1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:to="loc_RCATContractualMaturitiesPeriod1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ContractualMaturitiesPeriod2Member" xlink:label="loc_RCATContractualMaturitiesPeriod2Member_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:to="loc_RCATContractualMaturitiesPeriod2Member_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ContractualMaturitiesPeriod3Member" xlink:label="loc_RCATContractualMaturitiesPeriod3Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:to="loc_RCATContractualMaturitiesPeriod3Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ContractualMaturitiesTotalMember" xlink:label="loc_RCATContractualMaturitiesTotalMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesContractualMaturitiesDomain" xlink:to="loc_RCATContractualMaturitiesTotalMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsAtCarryingValue" xlink:label="loc_us-gaapMoneyMarketFundsAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapMoneyMarketFundsAtCarryingValue_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetBackedSecuritiesAtCarryingValue" xlink:label="loc_us-gaapAssetBackedSecuritiesAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAssetBackedSecuritiesAtCarryingValue_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CorporateBondsAtCarryingValue" xlink:label="loc_RCATCorporateBondsAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATCorporateBondsAtCarryingValue_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaapAvailableForSaleSecurities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAvailableForSaleSecurities_50" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/FairValueHierarchy" xlink:title="00000043 - Disclosure - Fair Value Hierarchy">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesFairValueHierarchyAxis" xlink:label="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:label="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyAxis" xlink:to="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:label="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyAxis" xlink:to="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesLevel1Member" xlink:label="loc_RCATAvailableForSaleSecuritiesLevel1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesLevel1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesLevel2Member" xlink:label="loc_RCATAvailableForSaleSecuritiesLevel2Member_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesLevel2Member_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesLevel3Member" xlink:label="loc_RCATAvailableForSaleSecuritiesLevel3Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesLevel3Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AvailableForSaleSecuritiesTotalMember" xlink:label="loc_RCATAvailableForSaleSecuritiesTotalMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAvailableForSaleSecuritiesFairValueHierarchyDomain" xlink:to="loc_RCATAvailableForSaleSecuritiesTotalMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsAtCarryingValue" xlink:label="loc_us-gaapMoneyMarketFundsAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapMoneyMarketFundsAtCarryingValue_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetBackedSecuritiesAtCarryingValue" xlink:label="loc_us-gaapAssetBackedSecuritiesAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAssetBackedSecuritiesAtCarryingValue_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CorporateBondsAtCarryingValue" xlink:label="loc_RCATCorporateBondsAtCarryingValue_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATCorporateBondsAtCarryingValue_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaapAvailableForSaleSecurities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAvailableForSaleSecurities_50" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/InventoriesDetails" xlink:title="00000044 - Disclosure - Inventories (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/OtherCurrentAssetsDetails" xlink:title="00000045 - Disclosure - Other current assets (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/PropertyAndEquipmentDetails" xlink:title="00000046 - Disclosure - Property and equipment (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/OperatingLeasesForRealEstateLocationsDetails" xlink:title="00000047 - Disclosure - operating leases for real estate locations (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis" xlink:label="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:label="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseAxis" xlink:to="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:label="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseAxis" xlink:to="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingLeaseLocation1Member" xlink:label="loc_RCATOperatingLeaseLocation1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="loc_RCATOperatingLeaseLocation1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingLeaseLocation2Member" xlink:label="loc_RCATOperatingLeaseLocation2Member_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="loc_RCATOperatingLeaseLocation2Member_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingLeaseLocation3Member" xlink:label="loc_RCATOperatingLeaseLocation3Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="loc_RCATOperatingLeaseLocation3Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingLeaseLocation4Member" xlink:label="loc_RCATOperatingLeaseLocation4Member_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="loc_RCATOperatingLeaseLocation4Member_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingLeaseLocation5Member" xlink:label="loc_RCATOperatingLeaseLocation5Member_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="loc_RCATOperatingLeaseLocation5Member_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OperatingLeaseLocation6Member" xlink:label="loc_RCATOperatingLeaseLocation6Member_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="loc_RCATOperatingLeaseLocation6Member_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseExpense" xlink:label="loc_us-gaapOperatingLeaseExpense_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapOperatingLeaseExpense_70" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/FutureLeasePaymentObligationsDetails" xlink:title="00000048 - Disclosure - Future lease payment obligations (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note8DebtObligationsDetailsNarrative" xlink:title="00000049 - Disclosure - Note 8 &#8211; Debt Obligations (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaapShortTermDebtLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaapScheduleOfShortTermDebtTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapScheduleOfShortTermDebtTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShortTermDebtTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation1Member" xlink:label="loc_RCATDebtObligation1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation2Member" xlink:label="loc_RCATDebtObligation2Member_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation2Member_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation3Member" xlink:label="loc_RCATDebtObligation3Member_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation3Member_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation4Member" xlink:label="loc_RCATDebtObligation4Member_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation4Member_90" xlink:type="arc" order="91" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation6Member" xlink:label="loc_RCATDebtObligation6Member_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation6Member_100" xlink:type="arc" order="101" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation7Member" xlink:label="loc_RCATDebtObligation7Member_130" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation7Member_130" xlink:type="arc" order="131" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation8Member" xlink:label="loc_RCATDebtObligation8Member_160" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation8Member_160" xlink:type="arc" order="161" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtObligation9Member" xlink:label="loc_RCATDebtObligation9Member_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDebtObligation9Member_190" xlink:type="arc" order="191" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaapDebtInstrumentFaceAmount_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentFaceAmount_220" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_220" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentPeriodicPayment" xlink:label="loc_us-gaapDebtInstrumentPeriodicPayment_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentPeriodicPayment_220" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaapDebtInstrumentCarryingAmount_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentCarryingAmount_220" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteAgreementAmount" xlink:label="loc_RCATConvertibleNoteAgreementAmount_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNoteAgreementAmount_220" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtInstrumentPeriodicPaymentFinalPaymentDue" xlink:label="loc_RCATDebtInstrumentPeriodicPaymentFinalPaymentDue_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtInstrumentPeriodicPaymentFinalPaymentDue_220" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_SBAPPPLoanAmountsReceived" xlink:label="loc_RCATSBAPPPLoanAmountsReceived_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATSBAPPPLoanAmountsReceived_220" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_LeaseholdImprovementAgreementFundsReceived" xlink:label="loc_RCATLeaseholdImprovementAgreementFundsReceived_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATLeaseholdImprovementAgreementFundsReceived_220" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_FinancingAgreementFundingOfPurchaseOfFixedAsset" xlink:label="loc_RCATFinancingAgreementFundingOfPurchaseOfFixedAsset_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATFinancingAgreementFundingOfPurchaseOfFixedAsset_220" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_FundsAdvancedPursuantToAgreement" xlink:label="loc_RCATFundsAdvancedPursuantToAgreement_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATFundsAdvancedPursuantToAgreement_220" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_TransactionFees" xlink:label="loc_RCATTransactionFees_220" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATTransactionFees_220" xlink:type="arc" order="10" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/AgreementsWithShopify" xlink:title="00000050 - Disclosure - Agreements with Shopify">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaapShortTermDebtLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaapScheduleOfShortTermDebtTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapScheduleOfShortTermDebtTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShortTermDebtTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_NotePayableShopifyCapital1Member" xlink:label="loc_RCATNotePayableShopifyCapital1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATNotePayableShopifyCapital1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_NotePayableShopifyCapital2Member" xlink:label="loc_RCATNotePayableShopifyCapital2Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATNotePayableShopifyCapital2Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_NotePayableShopifyCapital3Member" xlink:label="loc_RCATNotePayableShopifyCapital3Member_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATNotePayableShopifyCapital3Member_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_PurchasedReceivables" xlink:label="loc_RCATPurchasedReceivables_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATPurchasedReceivables_70" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:label="loc_us-gaapProceedsFromSaleOfProductiveAssets_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapProceedsFromSaleOfProductiveAssets_70" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_TransactionFees" xlink:label="loc_RCATTransactionFees_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATTransactionFees_70" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_WithholdingRate" xlink:label="loc_RCATWithholdingRate_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATWithholdingRate_70" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_EndingBalanceOfShopifyCapitalAgreements" xlink:label="loc_RCATEndingBalanceOfShopifyCapitalAgreements_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATEndingBalanceOfShopifyCapitalAgreements_70" xlink:type="arc" order="4" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/OutstandingPrincipalPaymentsDetails" xlink:title="00000051 - Disclosure - Outstanding principal payments (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note9-DueToRelatedPartyDetailsNarrative" xlink:title="00000052 - Disclosure - Note 9 - Due to Related Party (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaapShortTermDebtLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaapScheduleOfShortTermDebtTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapScheduleOfShortTermDebtTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShortTermDebtTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DueToRelatedParty1Member" xlink:label="loc_RCATDueToRelatedParty1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDueToRelatedParty1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DueToRelatedParty2Member" xlink:label="loc_RCATDueToRelatedParty2Member_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDueToRelatedParty2Member_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DueToRelatedParty3Member" xlink:label="loc_RCATDueToRelatedParty3Member_80" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATDueToRelatedParty3Member_80" xlink:type="arc" order="81" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_PromissoryNoteOriginalPrincipalAmount" xlink:label="loc_RCATPromissoryNoteOriginalPrincipalAmount_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATPromissoryNoteOriginalPrincipalAmount_120" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_120" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_RefundRelatedToPrepaidInventoryIssuedByCompany" xlink:label="loc_RCATRefundRelatedToPrepaidInventoryIssuedByCompany_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATRefundRelatedToPrepaidInventoryIssuedByCompany_120" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtInstrumentOutstandingBalancePayment" xlink:label="loc_RCATDebtInstrumentOutstandingBalancePayment_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtInstrumentOutstandingBalancePayment_120" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtInstrumentOutstandingAccruedInterestPayment" xlink:label="loc_RCATDebtInstrumentOutstandingAccruedInterestPayment_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtInstrumentOutstandingAccruedInterestPayment_120" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtInstrumentInterestRateDuringPeriod1" xlink:label="loc_RCATDebtInstrumentInterestRateDuringPeriod1_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtInstrumentInterestRateDuringPeriod1_120" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtInstrumentInterestRateDuringPeriod2" xlink:label="loc_RCATDebtInstrumentInterestRateDuringPeriod2_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtInstrumentInterestRateDuringPeriod2_120" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToOtherRelatedPartiesClassifiedCurrent" xlink:label="loc_us-gaapDueToOtherRelatedPartiesClassifiedCurrent_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDueToOtherRelatedPartiesClassifiedCurrent_120" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AdvancesReceivedFromRelatedParty" xlink:label="loc_RCATAdvancesReceivedFromRelatedParty_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATAdvancesReceivedFromRelatedParty_120" xlink:type="arc" order="8" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note10-ConvertibleNotesDetailsNarrative" xlink:title="00000053 - Disclosure - Note 10 - Convertible Notes (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaapShortTermDebtLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaapScheduleOfShortTermDebtTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapScheduleOfShortTermDebtTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShortTermDebtTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleDebenture2019NotesMember" xlink:label="loc_RCATConvertibleDebenture2019NotesMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATConvertibleDebenture2019NotesMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleDebenture2020NotesMember" xlink:label="loc_RCATConvertibleDebenture2020NotesMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATConvertibleDebenture2020NotesMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleDebenture2021NotesMember" xlink:label="loc_RCATConvertibleDebenture2021NotesMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_RCATConvertibleDebenture2021NotesMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteIssuedAccreditedInvestor" xlink:label="loc_RCATConvertibleNoteIssuedAccreditedInvestor_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNoteIssuedAccreditedInvestor_100" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteIssuedDirector" xlink:label="loc_RCATConvertibleNoteIssuedDirector_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNoteIssuedDirector_100" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteIssuedChiefExecutiveOfficer" xlink:label="loc_RCATConvertibleNoteIssuedChiefExecutiveOfficer_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNoteIssuedChiefExecutiveOfficer_100" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaapDebtInstrumentTerm_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentTerm_100" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_100" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNotesPrincipalConversion" xlink:label="loc_RCATConvertibleNotesPrincipalConversion_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNotesPrincipalConversion_100" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNotesAccruedInterestConversion" xlink:label="loc_RCATConvertibleNotesAccruedInterestConversion_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNotesAccruedInterestConversion_100" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNotesConversionShares" xlink:label="loc_RCATConvertibleNotesConversionShares_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertibleNotesConversionShares_100" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertiblePromissoryNotePrincipalAmount" xlink:label="loc_RCATConvertiblePromissoryNotePrincipalAmount_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATConvertiblePromissoryNotePrincipalAmount_100" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_WarrantsToPurchaseCommonStock" xlink:label="loc_RCATWarrantsToPurchaseCommonStock_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATWarrantsToPurchaseCommonStock_100" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DerivativeLiabilityInitialValue" xlink:label="loc_RCATDerivativeLiabilityInitialValue_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDerivativeLiabilityInitialValue_100" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtDiscountToReduceInitialCarryingValueOfNotes" xlink:label="loc_RCATDebtDiscountToReduceInitialCarryingValueOfNotes_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtDiscountToReduceInitialCarryingValueOfNotes_100" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DebtDiscountAppliedAgainstTransactionFees" xlink:label="loc_RCATDebtDiscountAppliedAgainstTransactionFees_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDebtDiscountAppliedAgainstTransactionFees_100" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DerivativeLiabilityValueRelatedToDerivativeFeaturesOfNotes" xlink:label="loc_RCATDerivativeLiabilityValueRelatedToDerivativeFeaturesOfNotes_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDerivativeLiabilityValueRelatedToDerivativeFeaturesOfNotes_100" xlink:type="arc" order="13" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DerivativeLiabilityValueRelatedToDerivativeFeaturesOfWarrants" xlink:label="loc_RCATDerivativeLiabilityValueRelatedToDerivativeFeaturesOfWarrants_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATDerivativeLiabilityValueRelatedToDerivativeFeaturesOfWarrants_100" xlink:type="arc" order="14" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_WarrantsOutstanding" xlink:label="loc_RCATWarrantsOutstanding_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_RCATWarrantsOutstanding_100" xlink:type="arc" order="15" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaapDerivativeLiabilities_100" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDerivativeLiabilities_100" xlink:type="arc" order="16" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note11-IncomeTaxesDetailsNarrative" xlink:title="00000054 - Disclosure - Note 11 - Income Taxes (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note12-CommonStockDetailsNarrative" xlink:title="00000055 - Disclosure - Note 12 - Common Stock (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaapClassOfStockLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaapScheduleOfStockByClassTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapScheduleOfStockByClassTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfStockByClassTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CommonStockOffering1Member" xlink:label="loc_RCATCommonStockOffering1Member_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_RCATCommonStockOffering1Member_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_CommonStockOffering2Member" xlink:label="loc_RCATCommonStockOffering2Member_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_RCATCommonStockOffering2Member_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfStockByClassTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_SeriesAPreferredStock1Member" xlink:label="loc_RCATSeriesAPreferredStock1Member_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_RCATSeriesAPreferredStock1Member_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_90" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:label="loc_us-gaapSaleOfStockNumberOfSharesIssuedInTransaction_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapSaleOfStockNumberOfSharesIssuedInTransaction_90" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_SaleOfStockGrossConsiderationReceivedOnTransaction" xlink:label="loc_RCATSaleOfStockGrossConsiderationReceivedOnTransaction_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_RCATSaleOfStockGrossConsiderationReceivedOnTransaction_90" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:label="loc_us-gaapSaleOfStockConsiderationReceivedOnTransaction_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapSaleOfStockConsiderationReceivedOnTransaction_90" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesOther_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesOther_90" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_90" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesRestrictedStockAwardGross_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesRestrictedStockAwardGross_90" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_90" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesIssuedForServices_90" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_StockIssuedDuringPeriodSharesAcquisitions1" xlink:label="loc_RCATStockIssuedDuringPeriodSharesAcquisitions1_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_RCATStockIssuedDuringPeriodSharesAcquisitions1_90" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesShareBasedCompensation_90" xlink:type="arc" order="11" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note13-PreferredStockDetailsNarrative" xlink:title="00000056 - Disclosure - Note 13 - Preferred Stock (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaapClassOfStockLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaapScheduleOfStockByClassTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapScheduleOfStockByClassTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfStockByClassTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesAPreferredStockMember" xlink:label="loc_us-gaapSeriesAPreferredStockMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesAPreferredStockMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeriesBPreferredStockMember" xlink:label="loc_us-gaapSeriesBPreferredStockMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesBPreferredStockMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_SeriesAPreferredStockSharesExemptFromReverseStockSplit" xlink:label="loc_RCATSeriesAPreferredStockSharesExemptFromReverseStockSplit_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_RCATSeriesAPreferredStockSharesExemptFromReverseStockSplit_60" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding_60" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_PreferredStockSharesConvertedCommonStockSharesIssued" xlink:label="loc_RCATPreferredStockSharesConvertedCommonStockSharesIssued_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_RCATPreferredStockSharesConvertedCommonStockSharesIssued_60" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_PreferredStockSharesConvertibleIntoCommonStockShares" xlink:label="loc_RCATPreferredStockSharesConvertibleIntoCommonStockShares_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_RCATPreferredStockSharesConvertibleIntoCommonStockShares_60" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/ChangesInWarrantsOutstandingDetails" xlink:title="00000057 - Disclosure - changes in warrants outstanding (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightLineItems" xlink:label="loc_us-gaapClassOfWarrantOrRightLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="loc_us-gaapClassOfWarrantOrRightTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapClassOfWarrantOrRightTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="loc_us-gaapClassOfWarrantOrRightAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapClassOfWarrantOrRightTable" xlink:to="loc_us-gaapClassOfWarrantOrRightAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaapClassOfWarrantOrRightDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapClassOfWarrantOrRightAxis" xlink:to="loc_us-gaapClassOfWarrantOrRightDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaapClassOfWarrantOrRightDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapClassOfWarrantOrRightAxis" xlink:to="loc_us-gaapClassOfWarrantOrRightDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_WarrantsOutstanding1Member" xlink:label="loc_RCATWarrantsOutstanding1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightDomain" xlink:to="loc_RCATWarrantsOutstanding1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_60" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaapSharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapSharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_60" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_60" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_60" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_60" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_60" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_60" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfWarrantOrRightLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_60" xlink:type="arc" order="7" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note14-WarrantsDetailsNarrative" xlink:title="00000058 - Disclosure - Note 14 - Warrants (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/AssumptionsUsedToCalculateFairValueOfOptionsGrantedDetails" xlink:title="00000059 - Disclosure - assumptions used to calculate the fair value of options granted (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_FairValueOfOptionsAxis" xlink:label="loc_RCATFairValueOfOptionsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_RCATFairValueOfOptionsAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_FairValueOfOptionsDomain" xlink:label="loc_RCATFairValueOfOptionsDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_RCATFairValueOfOptionsAxis" xlink:to="loc_RCATFairValueOfOptionsDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_FairValueOfOptionsDomain" xlink:label="loc_RCATFairValueOfOptionsDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_RCATFairValueOfOptionsAxis" xlink:to="loc_RCATFairValueOfOptionsDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OptionsAssumptionsMember" xlink:label="loc_RCATOptionsAssumptionsMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATFairValueOfOptionsDomain" xlink:to="loc_RCATOptionsAssumptionsMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePriceMinimum" xlink:label="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePriceMinimum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePriceMinimum_20" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePriceMaximum" xlink:label="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePriceMaximum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePriceMaximum_20" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsStockPriceOnDateOfGrantMinimum" xlink:label="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsStockPriceOnDateOfGrantMinimum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsStockPriceOnDateOfGrantMinimum_20" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsStockPriceOnDateOfGrantMaximum" xlink:label="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsStockPriceOnDateOfGrantMaximum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_RCATShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsStockPriceOnDateOfGrantMaximum_20" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_20" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_20" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_20" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_20" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_20" xlink:type="arc" order="8" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note15-ShareBasedAwardsDetailsNarrative" xlink:title="00000060 - Disclosure - Note 15 - Share Based Awards (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/SummaryOfActivityUnderPlan" xlink:title="00000061 - Disclosure - Summary of activity under the Plan">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="loc_us-gaapScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:to="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_Options1Member" xlink:label="loc_RCATOptions1Member_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="loc_RCATOptions1Member_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_60" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaapSharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapSharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_60" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_60" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_60" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesStockOptionsExercised_60" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_60" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares" xlink:label="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapSharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares_60" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_60" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_60" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_60" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="loc_us-gaapSharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapSharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_60" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_60" xlink:type="arc" order="12" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/StockCompensationExpenseDetails" xlink:title="00000062 - Disclosure - Stock compensation expense (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/AssumptionsUsedToDetermineFairValueOfDerivativeWarrantLiability" xlink:title="00000063 - Disclosure - Assumptions used to determine fair value of derivative warrant liability">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AssumptionsFairValueDerivativeWarrantLiabilityAxis" xlink:label="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AssumptionsFairValueDerivativeWarrantLiabilityDomain" xlink:label="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityAxis" xlink:to="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_AssumptionsFairValueDerivativeWarrantLiabilityDomain" xlink:label="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityAxis" xlink:to="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_DerivativeWarrantLiabilityMember" xlink:label="loc_RCATDerivativeWarrantLiabilityMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_RCATAssumptionsFairValueDerivativeWarrantLiabilityDomain" xlink:to="loc_RCATDerivativeWarrantLiabilityMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_20" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_20" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_20" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_20" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum" xlink:label="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_20" xlink:type="arc" order="4" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/ChangesInDerivativeLiabilityDetails" xlink:title="00000064 - Disclosure - Changes in the derivative liability (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://RCAT/role/Note17-Related-partyTransactionsDetailsNarrative" xlink:title="00000065 - Disclosure - Note 17 - Related-Party Transactions (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaapRelatedPartyTransactionLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_RelatedPartyMember" xlink:label="loc_RCATRelatedPartyMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_RCATRelatedPartyMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_Director1Member" xlink:label="loc_RCATDirector1Member_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_RCATDirector1Member_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteIssuedAccreditedInvestor" xlink:label="loc_RCATConvertibleNoteIssuedAccreditedInvestor_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConvertibleNoteIssuedAccreditedInvestor_40" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteIssuedDirector" xlink:label="loc_RCATConvertibleNoteIssuedDirector_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConvertibleNoteIssuedDirector_40" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNoteIssuedChiefExecutiveOfficer" xlink:label="loc_RCATConvertibleNoteIssuedChiefExecutiveOfficer_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConvertibleNoteIssuedChiefExecutiveOfficer_40" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaapDebtInstrumentTerm_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapDebtInstrumentTerm_40" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapDebtInstrumentInterestRateDuringPeriod_40" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNotesPrincipalConversion" xlink:label="loc_RCATConvertibleNotesPrincipalConversion_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConvertibleNotesPrincipalConversion_40" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNotesAccruedInterestConversion" xlink:label="loc_RCATConvertibleNotesAccruedInterestConversion_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConvertibleNotesAccruedInterestConversion_40" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConvertibleNotesConversionShares" xlink:label="loc_RCATConvertibleNotesConversionShares_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConvertibleNotesConversionShares_40" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_ConsultingAgreementMonthlyPayments" xlink:label="loc_RCATConsultingAgreementMonthlyPayments_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATConsultingAgreementMonthlyPayments_40" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OptionsToPurchaseCommonStockIssuedPursuantToConsultingAgreement" xlink:label="loc_RCATOptionsToPurchaseCommonStockIssuedPursuantToConsultingAgreement_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATOptionsToPurchaseCommonStockIssuedPursuantToConsultingAgreement_40" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="rcat-20211031.xsd#RCAT_OptionsToPurchaseCommonStockIssuedPursuantToConsutlingAgreementPurchasePrice" xlink:label="loc_RCATOptionsToPurchaseCommonStockIssuedPursuantToConsutlingAgreementPurchasePrice_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_RCATOptionsToPurchaseCommonStockIssuedPursuantToConsutlingAgreementPurchasePrice_40" xlink:type="arc" order="10" />
    </link:definitionLink>
</link:linkbase>
