The Northrop Delta was an American low-wing communication and passenger aircraft from the interwar period. The prototype's flight took place in 1933. The machine entered production in the same year. The drive - in the Delta 1D-5 version - was provided by a single motor Wright SR-1820 with 735 hp. The length of the aircraft was 10.08 meters with a wingspan of 14.55 meters. The machine did not have on-board weapons. The Delta model was designed and built by the American aircraft constructor Jack Northrop as a de facto evolutionary development of the Gamma mail aircraft. Compared to its predecessor, the new machine, among others: it was enlarged, it also had a greater maximum range and a completely redesigned interior. The license to manufacture this aircraft was purchased by Canadian Vickers Limited. Several variants of this aircraft have been developed in Canada, for example: the Delta Mk. I (version with a different power unit), Delta Mk. II (armed version intended for military aviation) or the Delta Mk. III. It is estimated that about 30-40 machines of this type were built in total, both in the USA and Canada.