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
Commuter Aircraft Corporation CAC-100 be supplied by four Pratt & Whitney Canada PT6A-65R turboprop engines driving five-bladed Hartzell Propeller constant speed reversible propellers. Production facilities were constructed at Youngstown, Ohio but the project was shelved in 1983 before its first flight. Commuter Aircraft Corporation CAC-100 The Commuter Aircraft Corporation CAC-100 was a 50–60 seat, four-engined, turboprop commuter airliner developed in the United States in the late 1970s and early 1980s.<ref name="JAWA81/82"></ref> The design of the CAC-100 originated from the General Aircraft Corporation GAC-100,<ref name="JAWA70/71"></ref> designed in the late 1960s. The GAC-100 design was enlarged and new technologies incorporated to produce the CAC-100. The proposed