Information I was given for including AircraftID for a dataset (IE, IceBridge) was to use an AdditionalAttribute tag, like this:
<eos:AdditionalAttributes>
<eos:AdditionalAttribute>
<eos:reference>
<eos:EOS_AdditionalAttributeDescription>
<eos:name>
<gco:CharacterString>AircraftID</gco:CharacterString>
</eos:name>
<eos:description>
<gco:CharacterString>The identifier of the airplane used by the FAA to uniquely identify each aircraft</gco:CharacterString>
</eos:description>
<eos:dataType>
<eos:EOS_AdditionalAttributeDataTypeCode codeList="http://earthdata.nasa.gov/metadata/resources/Codelists.xml#EOS_AdditionalAttributeDataTypeCode" codeListValue="STRING">STRING</eos:EOS_AdditionalAttributeDataTypeCode>
</eos:dataType>
</eos:EOS_AdditionalAttributeDescription>
</eos:reference>
<eos:value>
<gco:CharacterString>**Actual ID Goes Here**</gco:CharacterString>
</eos:value>
</eos:AdditionalAttribute>
</eos:AdditionalAttributes>
The main question I have with this, however, is how this aircraft ID will be linked with the actual aircraft/platform from the platform section?