Douglas DC-7 / AmericanDouglas DC 7 American Airlines model airplane. Douglas' largest and last piston engined airliner, the DC 7 was one of the first airliners capable of nonstop trans Atlantic crossings between New York and London. Previously the DC 7 designation had applied to a commercial development of the C74 Globemaster I that PanAm had ordered. As it emerged though the DC 7 arose from an American Airlines requirement for a stretched longer range development of the