V/STOL

A vertical and/or short take-off and landing (V/STOL) aircraft is an airplane able to take off or land vertically or on short runways. Vertical takeoff and landing (VTOL) aircraft are a subset of V/STOL craft that do not require runways at all. Generally, a V/STOL aircraft needs to be able to hover. Helicopters are not considered under the V/STOL classification as the classification is only used for aeroplanes, aircraft that achieve lift in forward flight by planing the air, thereby achieving speed and fuel efficiency that is typically greater than the capability of helicopters.

The main advantage of V/STOL aircraft is in their military performance, such as closer basing to the enemy, which reduces response time and tanker support requirements. In the case of the Falklands War, it also permitted high-performance fighter air cover and ground attack without a large aircraft carrier equipped with aircraft catapult. V/STOL was developed to allow fast jets to be operated from clearings in forests, from very short runways, and from small aircraft carriers that would previously only have been able to carry helicopters.

A rolling takeoff, sometimes with a ramp (ski-jump), reduces the amount of thrust required to lift an aircraft from the ground (compared with vertical takeoff), and hence increases the payload and range that can be achieved for a given thrust. For instance, the Harrier is incapable of taking off vertically with full weapons and fuel load. Hence V/STOL aircraft generally use a runway if it is available. In other words, short takeoff and vertical landing (STOVL) or conventional takeoff and landing (CTOL) operation is preferred to vertical takeoff and landing (VTOL) operation.

On aircraft carriers, non-catapult-assisted fixed-wing short takeoffs are accomplished with the use of thrust vectoring, which may also be used in conjunction with a runway "ski-jump". There are 16 aircraft carriers that operate these STOVL aircraft: United States (9), Japan (2), United Kingdom (2), Italy (2), and Spain (1). Use of STOVL tends to allow aircraft to carry a larger payload compared to vertical take-off and landing (VTOL), while still only requiring a short runway. The most famous examples are the Hawker Siddeley Harrier and the BAe Sea Harrier. Although technically a V/STOL aircraft, they are operationally STOVL aircraft due to the extra weight carried at take-off for fuel and armaments. The same is true of the B variant of the Lockheed Martin F-35 Lightning II, which demonstrated VTOL capability in test flights but is operationally a STOVL.