-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 FlOkYeSUKjAG5z1MUrTW7AoAFjlO3Nmd57DFK9wFWZAPfkgAtQWis+rbrbdCGL7m
 Ple803aLBhuP4Uo51QG0NQ==

<SEC-DOCUMENT>0001185849-04-000002.txt : 20040220
<SEC-HEADER>0001185849-04-000002.hdr.sgml : 20040220
<ACCEPTANCE-DATETIME>20040220124759
ACCESSION NUMBER:		0001185849-04-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040218
FILED AS OF DATE:		20040220

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ADDOMS SAMUEL D
		CENTRAL INDEX KEY:			0001251870

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12805
		FILM NUMBER:		04618512

	BUSINESS ADDRESS:	
		STREET 1:		C/O FRONTIER AIRLINES
		STREET 2:		7001 TOWER ROAD
		CITY:			DENVER
		STATE:			CO
		ZIP:			80249-7312
		BUSINESS PHONE:		7203744512

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FRONTIER AIRLINES INC /CO/
		CENTRAL INDEX KEY:			0000921929
		STANDARD INDUSTRIAL CLASSIFICATION:	AIR TRANSPORTATION, SCHEDULED [4512]
		IRS NUMBER:				841256945
		STATE OF INCORPORATION:			CO
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		7001 TOWER ROAD
		CITY:			DENVER
		STATE:			CO
		ZIP:			80249
		BUSINESS PHONE:		7203744200

	MAIL ADDRESS:	
		STREET 1:		7001 TOWER ROAD
		CITY:			DENVER
		STATE:			CO
		ZIP:			80249
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-02-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000921929</issuerCik>
        <issuerName>FRONTIER AIRLINES INC /CO/</issuerName>
        <issuerTradingSymbol>frnt</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251870</rptOwnerCik>
            <rptOwnerName>ADDOMS SAMUEL D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7001 TOWER ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80249</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.5021</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>104512.72</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Mr. Addoms owns 94,512.72 shares directly and 10,000 shares indirectly through his wife.</footnote>
        <footnote id="F2">Represents the average sale price for multiple trades completed on the same day.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>David Sislowski, Attorney in Fact</signatureName>
        <signatureDate>2004-02-20</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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