<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>5</documentType><periodOfReport>2003-12-31</periodOfReport><notSubjectToSection16>1</notSubjectToSection16><form3HoldingsReported>0</form3HoldingsReported><form4TransactionsReported>0</form4TransactionsReported><issuer><issuerCik>0001093434</issuerCik><issuerName>AETHER SYSTEMS INC</issuerName>        <issuerTradingSymbol>AETH</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001234932</rptOwnerCik><rptOwnerName>VANDERMEULEN KENDRA</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>C/O AETHER SYSTEMS</rptOwnerStreet1><rptOwnerStreet2>11460 CRONRIDGE DRIVE</rptOwnerStreet2><rptOwnerCity>OWINGS MILLS</rptOwnerCity><rptOwnerState>MD</rptOwnerState><rptOwnerZipCode>21117</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>2003-12-30</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>25000.0000</value></transactionShares><transactionPricePerShare><value>2.9500</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-30</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>25000.0000</value></transactionShares><transactionPricePerShare><value>4.6600</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Employee Stock Option</value></securityTitle><conversionOrExercisePrice><value>2.9500</value></conversionOrExercisePrice><transactionDate><value>2003-12-30</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>25000.0000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2003-12-28</value></exerciseDate><expirationDate><value>2012-12-28</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000.0000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes></footnotes><remarks></remarks><ownerSignature><signatureName>Kendra A. VanderMeulen</signatureName><signatureDate>2004-01-16</signatureDate></ownerSignature></ownershipDocument>

