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 Hawker Harrier The Hawker Harrier was an experimental biplane torpedo bomber aircraft built by Hawker Aircraft to a specification issued in the 1920s for the RAF. In , the British Air Ministry laid down specifications for a high altitude bomber to replace the Hawker Horsley and for a coastal torpedo bomber (Specifications 23/25 and 24/25). As these specifications were similar, the Air Ministry announced that a single competition would be held to study aircraft submitted for both specifications. Sydney Camm of Hawker Aircraft designed the Harrier to meet the requirements of Specification 23/25, with the prototype ("J8325") first flying in