<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2019-11-08</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000092380</issuerCik>
        <issuerName>SOUTHWEST AIRLINES CO</issuerName>
        <issuerTradingSymbol>LUV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001067983</rptOwnerCik>
            <rptOwnerName>BERKSHIRE HATHAWAY INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3555 FARNAM STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>OMAHA</rptOwnerCity>
            <rptOwnerState>NE</rptOwnerState>
            <rptOwnerZipCode>68131</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000315090</rptOwnerCik>
            <rptOwnerName>BUFFETT WARREN E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3555 FARNAM STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>OMAHA</rptOwnerCity>
            <rptOwnerState>NE</rptOwnerState>
            <rptOwnerZipCode>68131</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>53649213</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">46,962,713 of the total reported securities are owned directly by the following subsidiaries of Berkshire Hathaway Inc. (&quot;Berkshire&quot;): Government Employees Insurance Company (1,034,747), Medical Protective Company (8,722) and National Indemnity Company (45,649,244).  In order to avoid double counting, shares of Common Stock reported as being owned by each of these subsidiaries only reflect shares that are owned directly by such subsidiary, and do not reflect any shares that such subsidiary may be deemed to beneficially own by virtue of ownership or control of any other subsidiary otherwise reported in this Form 3.</footnote>
        <footnote id="F2">Continued from footnote 1: As Berkshire is in the chain of ownership of each subsidiary listed above, it may be deemed presently to both
beneficially own and have a pecuniary interest in all shares of Common Stock presently directly owned by such subsidiaries. Warren E. Buffett,
as the controlling stockholder of Berkshire, may be deemed presently to beneficially own, but only to the extent he has a pecuniary interest in,
the shares of Common Stock presently owned by each of these subsidiaries. Mr. Buffett disclaims beneficial ownership of these reported securities
except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F3">6,956,500 of the total reported securities are owned directly by the following pension plans of Berkshire's subsidiaries: Berkshire Hathaway Consolidated Pension Plan Master Retirement Trust (6,700,000), Buffalo News Driver/Distributors Pension Plan (6,500), and Precision CastParts Corp Master Trust (250,000).  Each of Berkshire, Mr. Buffett and these pension plans disclaim beneficial ownership in such shares.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Warren E. Buffett, on behalf of himself and each other reporting person hereunder</signatureName>
        <signatureDate>2019-11-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
