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        <link:definition>9955541 - Disclosure - Acquisition of Sun Country Airlines Holdings, Inc.- Business Combination, Employee Benefit Plans Activity (Details)</link:definition>
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        <link:definition>9955542 - Disclosure - Acquisition of Sun Country Airlines Holdings, Inc.- Business Combination, Pro Forma Information (Details)</link:definition>
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        <link:definition>9955543 - Disclosure - Subsequent Events (Details)</link:definition>
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  <xs:element id="algt_PreCombinationValueOfReplacedAndAcceleratedEquityAwardsMember" abstract="true" name="PreCombinationValueOfReplacedAndAcceleratedEquityAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="algt_ConsiderationPaidWithRespectToAmazonMember" abstract="true" name="ConsiderationPaidWithRespectToAmazonMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="algt_TerminationPaymentUnderTaxReceivableAgreementMember" abstract="true" name="TerminationPaymentUnderTaxReceivableAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredRestrictedCash" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredRestrictedCash" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredShortTermInvestment" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredShortTermInvestment" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredShortTermLessorMaintenanceDeposits" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredShortTermLessorMaintenanceDeposits" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredExpendablePartsSuppliesAndFuelNet" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredExpendablePartsSuppliesAndFuelNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredPrepaidExpensesAndOtherCurrentAssets" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredPrepaidExpensesAndOtherCurrentAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredLongTermInvestment" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredLongTermInvestment" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredOperatingLeaseRightOfUseAssetsNet" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredOperatingLeaseRightOfUseAssetsNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedAssetAcquiredDepositsAndOtherAssets" abstract="false" name="BusinessCombinationRecognizedAssetAcquiredDepositsAndOtherAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAcquiredIncludingGoodwill" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedOperatingLeaseLiabilitiesCurrent" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedOperatingLeaseLiabilitiesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedAirTrafficLiability" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedAirTrafficLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedCurrentLoyaltyProgramLiability" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedCurrentLoyaltyProgramLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedCurrentMaturitiesOfLongTermDebtAndFinanceLeaseObligationsNetOfRelatedCosts" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedCurrentMaturitiesOfLongTermDebtAndFinanceLeaseObligationsNetOfRelatedCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedLongTermDebtAndFinanceLeaseObligationsNetOfCurrentMaturitiesAndRelatedCosts" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedLongTermDebtAndFinanceLeaseObligationsNetOfCurrentMaturitiesAndRelatedCosts" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedOperatingLeaseLiabilitiesNoncurrent" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedOperatingLeaseLiabilitiesNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationRecognizedLiabilityAssumedLoyaltyProgramLiabilityNoncurrent" abstract="false" name="BusinessCombinationRecognizedLiabilityAssumedLoyaltyProgramLiabilityNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="algt_BusinessCombinationNumberOfStockSharesGranted" abstract="false" name="BusinessCombinationNumberOfStockSharesGranted" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="algt_BusinessCombinationNumberOfStockSharesVested" abstract="false" name="BusinessCombinationNumberOfStockSharesVested" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="algt_BusinessCombinationNumberOfStockSharesForfeited" abstract="false" name="BusinessCombinationNumberOfStockSharesForfeited" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="algt_BusinessCombinationNumberOfStockSharesNonVested" abstract="false" name="BusinessCombinationNumberOfStockSharesNonVested" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="algt_BusinessCombinationGrantDateFairValue" abstract="false" name="BusinessCombinationGrantDateFairValue" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="algt_CreditAgreementDBJ22Member" abstract="true" name="CreditAgreementDBJ22Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="algt_CreditAgreementPDP3Member" abstract="true" name="CreditAgreementPDP3Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="algt_CreditAgreementMeritMember" abstract="true" name="CreditAgreementMeritMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="algt_CreditAgreementCANSB234Member" abstract="true" name="CreditAgreementCANSB234Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
