Almost the quintessential 1930s streamline style airplane, the Northrop Delta was a passenger development of the earlier Gamma. A change in US airline regulations specified multiple engines for airliners and the Delta was obsolete soon after being introduced.
The Royal Canadian Air Force had tested the Gamma and decided they needed a plane like that. The Gamma was not available and the Delta was adopted instead, serving as a survey plane and general use aircraft. Canadian Vickers obtained the license and built nineteen between 1936 and 1940. The aircraft was withdrawn from service a year later and served as airframe instruction aids in several schools though the 1940s.
A fuselage of a crashed example currently resides at the Canadian Air and Space museum in Ottawa.