Regional airliner were replaced by progressively longer-range designs. In the immediate post-war era these were typically Douglas DC-3s, although even the De Havilland Dragon Rapide biplane airliner remained in service for some time. This "hand-me-down" process of supplying aircraft continued with designs like the Convair 440, Douglas DC-6 and Vickers Viscount also serving in this role while the first jets were introduced. By the mid-1950s, demand for even more economical designs led to the production of the first custom feederliners. These were almost always turboprops, which had fuel economy on par with piston engine designs, but had far lower maintenance costs. Often
Vickers Viscount a post-war small medium-range pressurised aircraft to fly less-travelled routes, carrying 24 passengers up to 1,750 mi (2,816 km) at 200 mph (320 km/h). During discussions between the committee and Vickers' chief designer, Rex Pierson, Vickers advocated turboprop power. The committee was not convinced and split the specification into two types, the Type IIA using piston power, which led to the Airspeed Ambassador, and the turboprop-powered Type IIB which Vickers was selected to develop in April 1945. British European Airways (BEA) was involved in the design and asked that the aircraft carry 32 passengers instead, but remained otherwise similar. The