-----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,
 AxMeLc2DvBzxXqf2uH3R3Riwnvt1t5Ir9f6e3PJyn4JOHZsawwWuY4K2qH6S5gqz
 BToY2XB1A1302LSYW9Wq/A==

<SEC-DOCUMENT>0000001750-08-000069.txt : 20081010
<SEC-HEADER>0000001750-08-000069.hdr.sgml : 20081010
<ACCEPTANCE-DATETIME>20081010102055
ACCESSION NUMBER:		0000001750-08-000069
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20081010
FILED AS OF DATE:		20081010
DATE AS OF CHANGE:		20081010

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AAR CORP
		CENTRAL INDEX KEY:			0000001750
		STANDARD INDUSTRIAL CLASSIFICATION:	AIRCRAFT & PARTS [3720]
		IRS NUMBER:				362334820
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0531

	BUSINESS ADDRESS:	
		STREET 1:		1100 N WOOD DALE RD
		CITY:			WOOD DALE
		STATE:			IL
		ZIP:			60191
		BUSINESS PHONE:		6302272000

	MAIL ADDRESS:	
		STREET 1:		1100 N WOOD DALE RD
		CITY:			WOOD DALE
		STATE:			IL
		ZIP:			60191

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEN AIRCRAFT RADIO INC
		DATE OF NAME CHANGE:	19700204

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STORCH DAVID P
		CENTRAL INDEX KEY:			0001027741
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0531

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06263
		FILM NUMBER:		081117386

	BUSINESS ADDRESS:	
		STREET 1:		C/O AAR CORP
		STREET 2:		1111 NICHOLAS BLVD
		CITY:			ELK GROVE VILLAGE
		STATE:			IL
		ZIP:			60007
		BUSINESS PHONE:		8474393939

	MAIL ADDRESS:	
		STREET 1:		C/O AAR CORP
		STREET 2:		1111 NICHOLAS BLVD
		CITY:			1111 NICHOLAS BLVD
		STATE:			IL
		ZIP:			60007
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-10-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000001750</issuerCik>
        <issuerName>AAR CORP</issuerName>
        <issuerTradingSymbol>AIR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001027741</rptOwnerCik>
            <rptOwnerName>STORCH DAVID P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2>1100 WOOD DALE ROAD</rptOwnerStreet2>
            <rptOwnerCity>WOOD DALE</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60191</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-10-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.2</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>794396</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Jo-Ellen Kiddie, as Power of Attorney</signatureName>
        <signatureDate>2008-10-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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