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-Armstrongs A1E1 tank. One of the company's most important designs was the Valentine Infantry Tank, produced in the thousands in World War II. The military vehicle manufacturing interests were divested into Vickers plc, and would later pass to Alvis Vickers, now part of BAE Systems Land and Armaments. "Notable Vickers-Armstrongs military vehicles include;" Vickers formed its Aviation Department in 1911. The aircraft interests of Armstrong Whitworth were not acquired in the merger and later passed to the Hawker Aircraft group. In 1928 the Aviation Department became Vickers (Aviation) Ltd and soon after acquired Supermarine Aviation Works, which became the Supermarine Aviation