Harrier Jump Jet two systems are fully interlinked but air is not supplied to the reaction control valves during conventional wingborne flight. Harrier Jump Jet The Harrier, informally referred to as the Harrier Jump Jet, is a family of jet-powered attack aircraft capable of vertical/short takeoff and landing operations (V/STOL). Named after a bird of prey, it was originally developed by British manufacturer Hawker Siddeley in the 1960s. The Harrier emerged as the only truly successful V/STOL design of the many attempted during that era, despite being a subsonic aircraft, unlike most of its competitors. It was conceived to operate from improvised bases,
Dornier Do 31 during its ferry flight to the 1969 Paris Air Show. It was the first, and so far only, vertical takeoff jet transport ever built. The project was cancelled in April 1970, although it made its final public flight on 4 May 1970 during the ILA in Hanover. One of the factors that led to the cancellation was the large drag and weight of the lift engine pods which reduced the useful payload and range compared to conventional transport aircraft. To cope with the complex and fast computations necessary for vertical takeoff, the Do 31 was equipped with a Dornier DO-960