The Harrier Jump Jet, officially referred to as Harrier or informally as the Jump Jet, is a British military-designed jet aircraft capable of Vertical/Short Takeoff and Landing (V/STOL) via vector thrust. The Harrier family was the only truly successful of its kind of the many designs that appeared in the 1960s.There are four main versions of the Harrier family: Hawker Siddeley Harrier, British Aerospace Sea Harrier, Boeing/BAE Systems AV-8B Harrier II, and BAE Systems/Boeing Harrier II. The Hawker Siddeley Harrier is the first generation version and is also known as the AV-8A Harrier. The Sea Harrier is a naval combat air defense. The AV-8B and BAE Harrier II are variants of the US and UK second generation Harrier aircraft.