<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e18df-6f40-7624-abdc-72832010e412,g:90c7379d-776a-4e34-89b3-f5b739698008-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://archer.com/role/CoverCover" xlink:type="simple" xlink:href="achr-20260810.xsd#CoverCover"/>
  <link:definitionLink xlink:role="http://archer.com/role/CoverCover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019e18df-6f40-7d7a-8005-6b8be4427e7c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_DocumentInformationTable_019e18df-6f40-7d7a-8005-6b8be4427e7c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019e18df-6f40-72c3-8484-127c49aeabd6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019e18df-6f40-7d7a-8005-6b8be4427e7c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019e18df-6f40-72c3-8484-127c49aeabd6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e18df-6f40-72c3-8484-127c49aeabd6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e18df-6f40-72c3-8484-127c49aeabd6" xlink:to="loc_us-gaap_ClassOfStockDomain_019e18df-6f40-72c3-8484-127c49aeabd6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019e18df-6f40-7d52-9492-19f48c6e7577" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019e18df-6f40-72c3-8484-127c49aeabd6" xlink:to="loc_us-gaap_ClassOfStockDomain_019e18df-6f40-7d52-9492-19f48c6e7577" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_019e18df-6f40-76be-be3a-0b9e2e5a74fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e18df-6f40-7d52-9492-19f48c6e7577" xlink:to="loc_us-gaap_CommonClassAMember_019e18df-6f40-76be-be3a-0b9e2e5a74fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember_019e18df-6f40-7aae-8b11-56f560eb6515" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019e18df-6f40-7d52-9492-19f48c6e7577" xlink:to="loc_us-gaap_WarrantMember_019e18df-6f40-7aae-8b11-56f560eb6515" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019e18df-6f40-7a2a-8430-9b8bf58e91f5" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_DocumentType_019e18df-6f40-7a2a-8430-9b8bf58e91f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019e18df-6f40-7913-bb01-117f911be6d6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_DocumentPeriodEndDate_019e18df-6f40-7913-bb01-117f911be6d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019e18df-6f40-7e73-816e-dfb10954b839" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityRegistrantName_019e18df-6f40-7e73-816e-dfb10954b839" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019e18df-6f40-7ccc-951e-dca32faeff7c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019e18df-6f40-7ccc-951e-dca32faeff7c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019e18df-6f40-7131-800e-f872d1cbf350" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityFileNumber_019e18df-6f40-7131-800e-f872d1cbf350" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019e18df-6f40-714c-b1df-2a6537d4363f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityTaxIdentificationNumber_019e18df-6f40-714c-b1df-2a6537d4363f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019e18df-6f40-763b-ae72-9adcd9a4c35d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityAddressAddressLine1_019e18df-6f40-763b-ae72-9adcd9a4c35d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019e18df-6f40-7ebd-9294-c8304388fb1d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityAddressCityOrTown_019e18df-6f40-7ebd-9294-c8304388fb1d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019e18df-6f40-7e97-9ab8-f6b62a913a80" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityAddressStateOrProvince_019e18df-6f40-7e97-9ab8-f6b62a913a80" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019e18df-6f40-7ec5-969e-baffe45ceecf" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityAddressPostalZipCode_019e18df-6f40-7ec5-969e-baffe45ceecf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019e18df-6f40-7abb-b1e9-a35a6c00cc4f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_CityAreaCode_019e18df-6f40-7abb-b1e9-a35a6c00cc4f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019e18df-6f40-75b7-84f8-407e4c2d51c1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_LocalPhoneNumber_019e18df-6f40-75b7-84f8-407e4c2d51c1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019e18df-6f40-7896-98c3-d372024ad9bc" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_WrittenCommunications_019e18df-6f40-7896-98c3-d372024ad9bc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019e18df-6f40-78d2-94ac-a5918fcb55b6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_SolicitingMaterial_019e18df-6f40-78d2-94ac-a5918fcb55b6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019e18df-6f40-74de-b05c-7d9fe1e1a7df" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_PreCommencementTenderOffer_019e18df-6f40-74de-b05c-7d9fe1e1a7df" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019e18df-6f40-7948-aef5-7058c8bc6aab" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019e18df-6f40-7948-aef5-7058c8bc6aab" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019e18df-6f40-72bd-8e66-1c640a77a5a9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityEmergingGrowthCompany_019e18df-6f40-72bd-8e66-1c640a77a5a9" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019e18df-6f40-716f-b2d0-9ba307dcf7d0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_Security12bTitle_019e18df-6f40-716f-b2d0-9ba307dcf7d0" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019e18df-6f40-7d4c-abfa-ca2310f5c2eb" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_TradingSymbol_019e18df-6f40-7d4c-abfa-ca2310f5c2eb" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019e18df-6f40-7b8d-868d-6df170361e76" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_SecurityExchangeName_019e18df-6f40-7b8d-868d-6df170361e76" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019e18df-6f40-76fe-98a5-032936e0ef6b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_EntityCentralIndexKey_019e18df-6f40-76fe-98a5-032936e0ef6b" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019e18df-6f40-731b-b30d-7c433fe85df4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019e18df-6f40-7487-94f2-e1fc3a86acae" xlink:to="loc_dei_AmendmentFlag_019e18df-6f40-731b-b30d-7c433fe85df4" xlink:type="arc" order="21"/>
  </link:definitionLink>
</link:linkbase>
