Sale in course of export or import depends on whether the transaction occasions movement or transfers title across the customs frontier. A sale or purchase is in the course of export only if it occasions the export or transfers documents of title after goods cross the customs frontier, and in the course of import only if it occasions the import or transfers documents of title before goods cross the customs frontier. The last sale before an export can also be deemed export linked if made after and for complying with the export agreement, subject to a prescribed dealer declaration. Purchases of aviation turbine fuel by specified carriers for international flights are treated as export sales.