On 22 July 1929, the Bremen launched its first catapult flight to New York. Mail carried on the flight was stamped with a serial number, with a total of 10,997 pieces carried. A few covers are known without a serial number.
Mail carried on-board originated from three sources — inland German sources, on-board seapost, and Danzig.
Most mail carried on-board bears a red Norddeutscher Lloyd cachet, and a black first-flight cachet.