From 1929, the German Norddeutscher Lloyd-liners and were fitted with compressed air-driven catapults designed by the "Heinkel Flugzeugwerke" to launch mail-planes. These ships served the route between Germany and the United States. The aircraft, carrying mail–bags, would be launched as a mail tender while the ship was still many hundreds of miles from its destination, thus speeding mail delivery by about a day. Initially, Heinkel He 12 aircraft were used before they were replaced by Junkers Ju 46, which were in turn replaced by the Vought V-85G.