<SEC-DOCUMENT>0001628280-25-055737.txt : 20251208
<SEC-HEADER>0001628280-25-055737.hdr.sgml : 20251208
<ACCEPTANCE-DATETIME>20251208090901
ACCESSION NUMBER:		0001628280-25-055737
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251208
FILED AS OF DATE:		20251208
DATE AS OF CHANGE:		20251208

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Brown Gregory Lewis
		CENTRAL INDEX KEY:			0002017273
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33160
		FILM NUMBER:		251554794

	MAIL ADDRESS:	
		STREET 1:		3801 S. OLIVER ST.
		STREET 2:		MC K11-60
		CITY:			WICHITA
		STATE:			KS
		ZIP:			67210

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Spirit AeroSystems Holdings, Inc.
		CENTRAL INDEX KEY:			0001364885
		STANDARD INDUSTRIAL CLASSIFICATION:	AIRCRAFT PART & AUXILIARY EQUIPMENT, NEC [3728]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				202436320
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3801 SOUTH OLIVER
		CITY:			WICHITA
		STATE:			KS
		ZIP:			67210
		BUSINESS PHONE:		316.526.9000

	MAIL ADDRESS:	
		STREET 1:		3801 SOUTH OLIVER
		CITY:			WICHITA
		STATE:			KS
		ZIP:			67210
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1765202938.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-12-08</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001364885</issuerCik>
        <issuerName>Spirit AeroSystems Holdings, Inc.</issuerName>
        <issuerTradingSymbol>SPR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002017273</rptOwnerCik>
            <rptOwnerName>Brown Gregory Lewis</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3801 S. OLIVER</rptOwnerStreet1>
            <rptOwnerStreet2>MC K11-60</rptOwnerStreet2>
            <rptOwnerCity>WICHITA</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>67210</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, Global Quality</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class  A  Common  Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-12-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4459</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-12-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>27864</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class  A  Common  Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>27864</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On December 8, 2025, pursuant to the Agreement and Plan of Merger among the issuer, The Boeing Company (Boeing) and Sphere Acquisition Corp., dated June 30, 2024 (the Merger
Agreement), each share of the Class A Common Stock (Share) of the issuer was automatically canceled and converted into the right to receive a number of shares of Boeing common stock equal to 0.1955 (the Exchange Ratio).</footnote>
        <footnote id="F2">Restricted stock units (RSUs), once vested and payable, would be settled in Shares on a one-for-one basis.</footnote>
        <footnote id="F3">On December 8, 2025, pursuant to the Merger Agreement, each outstanding RSU of the issuer held by the reporting person was automatically converted into an RSU of Boeing denominated in
shares of Boeing common stock (a Boeing RSU). The number of shares of Boeing common stock subject to each such Boeing RSU is equal to the product (rounded to the nearest whole number) of (i)
the total number of Shares subject to such issuer RSU immediately prior to the Effective Time (as defined in the Merger Agreement) multiplied by (ii) the Exchange Ratio. Any accrued but unpaid
dividend equivalents with respect to any such issuer RSU was assumed and became an obligation with respect to the applicable Boeing RSU. Each such Boeing RSU continues to be governed by the
same terms and conditions (including vesting terms) as were applicable to such issuer RSU immediately prior to the Effective Time.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ David Myers, Attorney-in-Fact</signatureName>
        <signatureDate>2025-12-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
