Hawker Siddeley much larger firms. Out of this decision, came the "order" that all future contracts being offered had to include agreements to merge companies. In 1959, Folland Aircraft was acquired, followed by de Havilland Aircraft Company and Blackburn Aircraft in 1960. In 1963, the names of the constituent companies were dropped, with products being rebranded as ""Hawker Siddeley"" or ""HS"". In this period, the company developed the first operational, and, by far, the most successful VTOL jet aircraft, the Harrier family. This aircraft remained in production into the 1990s and remains in service. In 1948, Hawker Siddeley acquired a factory in
Hawker Harrier February , the first of the competitors for the two specifications to fly. The Harrier was a two-seat biplane with single-bay wings powered by a geared Bristol Jupiter VIII radial engine. It was armed with one .303 in (7.7 mm) Vickers machine gun and one .303 in (7.7 mm) Lewis gun carrying a maximum of 1,000 lb (454 kg) of bombs. The prototype Harrier was tested at the Aeroplane and Armament Experimental Establishment (A & AEE) at Martlesham Heath in November 1927, where, while it met the requirements of Specification 23/25 and had satisfactory handling, the geared engine meant that