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 Type 170 Vanguard Vickers Type 170 Vanguard The Vickers Vanguard was a 1920s British airliner developed by Vickers Limited from the Victoria. Developed from the earlier Victoria with the introduction of a wider fuselage, the Vanguard was a 22-passenger twin-engined biplane. Originally built for the Air Ministry as the Type 62 the aircraft powered by two 450 hp Napier Lion engines first flew on 18 July 1923. It was re-engined in 1925 with two 650 hp Rolls-Royce Condor IIIs and re-designated the Type 103. When it was handed over to Imperial Airways in 1925 it was described as the "World's largest passenger aeroplane".