-----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,
 Rd8v/WAqv0VGtEOnRjU/dm6P6NdsMZImJxKIm/r3kKeEvPe4PKJQGHeyVOF2NP4f
 Hhx8+yZowXdAN6m6yiBZKQ==

<SEC-DOCUMENT>0000015847-08-000013.txt : 20080424
<SEC-HEADER>0000015847-08-000013.hdr.sgml : 20080424
<ACCEPTANCE-DATETIME>20080424125818
ACCESSION NUMBER:		0000015847-08-000013
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080424
FILED AS OF DATE:		20080424
DATE AS OF CHANGE:		20080424

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Seba-Shinabargar Angela D
		CENTRAL INDEX KEY:			0001325035

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-01678
		FILM NUMBER:		08773786

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		913-780-9595

	MAIL ADDRESS:	
		STREET 1:		11575 S. WATER
		CITY:			OLATHE
		STATE:			KS
		ZIP:			66061

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BUTLER NATIONAL CORP
		CENTRAL INDEX KEY:			0000015847
		STANDARD INDUSTRIAL CLASSIFICATION:	AIRCRAFT [3721]
		IRS NUMBER:				410834293
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0430

	BUSINESS ADDRESS:	
		STREET 1:		19920 W 161ST ST
		CITY:			OLATHE
		STATE:			KS
		ZIP:			66062
		BUSINESS PHONE:		8167809595

	MAIL ADDRESS:	
		STREET 1:		19920 W 161ST ST
		CITY:			OLATHE
		STATE:			KS
		ZIP:			66062

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NATIONAL CONNECTOR CORP
		DATE OF NAME CHANGE:	19701009
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-04-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000015847</issuerCik>
        <issuerName>BUTLER NATIONAL CORP</issuerName>
        <issuerTradingSymbol>buks</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001325035</rptOwnerCik>
            <rptOwnerName>Seba-Shinabargar Angela D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>11575 S. WATER</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>OLATHE</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66061</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Butler National Corporation common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-04-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.31</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>146092</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Butler National Corporation common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-04-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.3</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>121092</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ Angela D. Shinabargar</signatureName>
        <signatureDate>2008-04-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----