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 Aircraft it merged with the engine and automotive company Armstrong Siddeley and its subsidiary, Armstrong Whitworth Aircraft, to form Hawker Siddeley Aircraft. This group also encompassed A. V. Roe and Company (Avro). Hawker Aircraft continued to produce designs under its own name as part of Hawker Siddeley Aircraft, from 1955 a division of Hawker Siddeley Group. The "Hawker" brand name was dropped, along with those of the sister companies, in 1963; the Hawker P.1127 was the last aircraft to carry the brand. The Hawker legacy was maintained by the American company Raytheon who produced business jets (including some derived from the