Hawker Siddeley Harrier cancelled after the release of the British Government's 1957 Defence White Paper, which advocated a policy shift away from manned aircraft and towards missiles. This policy resulted in the termination of the majority of aircraft development projects then underway for the British military. Hawker sought to quickly move on to a new project and became interested in Vertical Take Off/Landing (VTOL) aircraft, which did not need runways. According to Air Chief Marshal Sir Patrick Hine this interest may have been stimulated by the presence of Air Staff Requirement 345, which sought a V/STOL ground attack fighter for the Royal Air
Hawker 400 aircraft like tankers and strategic transports: 180 were delivered between 1992 and 1997. The Japan Air Self-Defense Force 400T trainer shares the T1-A Type certificate. In 1993 Raytheon purchased the Hawker business jets from British Aerospace, renamed the Beechjet 400 as the Hawker 400 to include it in the line and the Hawker 400XP incorporated aerodynamic, mechanical and interior improvements from the Hawker 800XP. In October 2008, Hawker Beechcraft upgraded it as the Hawker 450XP including new, more fuel efficient Pratt & Whitney PW535Ds with 2,965 pounds of thrust each but it was canceled in June 2009 due to poor