(abbreviation for vertical/short takeoff and landing) Aircraft capable of taking off and landing either vertically or using a very short length of runway (see STOL). Vertical takeoff requires a vector-control system that permits the thrust of the aircraft engine to be changed from horizontal to vertical for takeoff and back again to horizontal to permit forward flight. An alternative VSTOL technology developed in the US involves tilting the wings of the aircraft from vertical to horizontal and along with them the aircraft propellers, thus changing from vertical lift to horizontal thrust.
The British Harrier fighter bomber was the first VSTOL aircraft. It is now manufactured under license in the US and provides integral air support for the US Marines. In addition to the UK's Royal Air Force and Royal Navy, the Indian, Spanish, and Italian navies are equipped with the Harrier. It was used in the 1982 Falklands conflict and the 1991 Gulf War.