XML 71 R46.htm IDEA: XBRL DOCUMENT
v3.25.2

Balance Sheet Information - Additional Information (Detail) | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2021 USD ($) shares | Jul. 31, 2021 USD ($) | Mar. 31, 2025 USD ($) AIRFRAMES AIRCRAFT | Mar. 31, 2024 USD ($) | Mar. 31, 2025 USD ($) | Mar. 31, 2024 USD ($) | Sep. 30, 2024 USD ($) | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($) | Feb. 28, 2022 USD ($) | Feb. 28, 2021 USD ($)
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Depreciation expense |  |  | $ 6,000,000 | $ 9,800,000 | $ 13,900,000 | $ 23,100,000 | $ 40,000,000 | $ 60,200,000 | $ 80,500,000 |  |
Estimated initial equity warrant asset value |  |  |  |  |  |  |  |  |  |  | $ 16,400,000
Investments in equity securities |  |  | 300,000 |  | $ 300,000 |  | 300,000 | 20,320,000 |  |  |
Total net unrealized gain/(loss) |  |  |  |  |  |  | (6,100) | 5,400,000 |  |  |
Estimated initial warrant asset value |  |  |  |  |  |  |  |  |  | $ 3,200,000 |
Total realized gain (loss) on equity securities |  |  |  |  |  |  | 8,000,000 | 0 |  |  |
Aggregate carrying amount of investments in equity securities |  |  |  |  |  |  | 300,000 | 20,300,000 |  |  |
Investments without readily determinable fair value |  |  |  |  |  |  | 300,000 | 8,800,000 |  |  |
Impairment true-up adjustment |  |  | 12,400,000 |  |  |  | 73,700,000 | 50,600,000 | $ 62,100,000 |  |
United Capacity Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Realized and unrealized gain (loss) on investment |  |  |  |  |  |  | 7,200,000 |  |  |  |
Debt reduction |  |  |  |  |  |  | 12,600,000 |  |  |  |
Engines Held For Sale [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Impairment true-up adjustment |  |  | $ 33,800 |  |  |  |  |  |  |  |
Archer Aviation, Inc. [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale |  |  |  |  |  |  | 9,600,000 |  |  |  |
Loss on sale |  |  |  |  |  |  | 800,000 |  |  |  |
Realized and unrealized gain (loss) on investment |  |  |  |  |  |  | (2,700,000) | $ 5,600,000 |  |  |
Heart Aerospace Incorporated [Member] | Forward Purchase Contract [Member] | Preferred Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Purchase of preferred stock |  | $ 5,000,000 |  |  |  |  |  |  |  |  |
Initial investment in preferred stock measured at cost |  | $ 5,000,000 |  |  |  |  |  |  |  |  |
VTOL Aircraft, XTI Aerospace, Inc [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Realized and unrealized gain (loss) on investment |  |  |  |  |  |  | (3,500,000) |  |  |  |
Investments in equity securities |  |  |  |  |  |  | $ 100,000 |  |  |  |
Class A [Member] | Archer Aviation, Inc. [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of shares sold | shares | 500,000 |  |  |  |  |  |  |  |  |  |
Proceeds from sale | $ 5,000,000 |  |  |  |  |  |  |  |  |  |
Total grant date value, Additional warrant to purchase shares | $ 5,600,000 |  |  |  |  |  |  |  |  |  |
C R J 900 Airframes [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of aircraft classified as assets held for sale | AIRFRAMES |  |  | 3 |  |  |  |  |  |  |  |
CF34-8C Engines [Member] |  |  |  |  |  |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of aircraft classified as assets held for sale | AIRCRAFT |  |  | 4 |  |  |  |  |  |  |  |

X
- Definition Estimated initial equity warrant asset value. + References No definition available. + Details
Name: | mesa_EstimatedInitialEquityWarrantAssetValue
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Estimated initial warrant asset value. + References No definition available. + Details
Name: | mesa_EstimatedInitialWarrantAssetValue
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Grant date value for additional warrant to purchase shares. + References No definition available. + Details
Name: | mesa_GrantDateValueForAdditionalWarrantToPurchaseShares
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Initial investment in preferred stock measured at cost. + References No definition available. + Details
Name: | mesa_InitialInvestmentInPreferredStockMeasuredAtCost
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of aircraft classified as assets held for sale. + References No definition available. + Details
Name: | mesa_NumberOfAircraftClassifiedAsAssetsHeldForSale
Namespace Prefix: | mesa_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 04 -Paragraph a -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481231/810-10-45-11 + Details
Name: | srt_CondensedBalanceSheetStatementsCaptionsLineItems
Namespace Prefix: | srt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Decrease for amounts of indebtedness forgiven by the holder of the debt instrument. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(f)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 + Details
Name: | us-gaap_DebtInstrumentDecreaseForgiveness
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-1 + Details
Name: | us-gaap_Depreciation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This element represents the aggregate cost of investments accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_EquityMethodInvestmentAggregateCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A + Details
Name: | us-gaap_EquitySecuritiesFVNINoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 321 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479536/321-10-50-4 + Details
Name: | us-gaap_EquitySecuritiesFvNiRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 321 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479536/321-10-50-4 + Details
Name: | us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment in equity security without readily determinable fair value. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 321 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479536/321-10-50-3 + Details
Name: | us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of realized and unrealized gain (loss) on investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(9)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(7)(c)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_GainLossOnInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of gain (loss) from the difference between the sale price or salvage price and the book value of an asset that was sold or retired, and gain (loss) from the write down of assets from their carrying value to fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 + Details
Name: | us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482130/360-10-45-15 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares of stock issued during the period pursuant to acquisitions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesAcquisitions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of stock issued pursuant to acquisitions during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(30)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(31)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockIssuedDuringPeriodValueAcquisitions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Value of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination. + References No definition available. + Details
Name: | us-gaap_StockIssuedDuringPeriodValuePurchaseOfAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=mesa_UnitedCapacityPurchaseAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mesa_EnginesHeldForSaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=mesa_ArcherAviationIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=mesa_HeartAerospaceIncorporatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mesa_ForwardPurchaseContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=mesa_VtolAircraftXtiAerospaceIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_AircraftTypeAxis=mesa_CRJ900AirframesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_AircraftTypeAxis=mesa_CF34-8CEnginesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |