vertical takeoff and landing aircraft (VTOL), craft capable of rising and descending vertically from and to the ground, thus requiring no runway. While a balloon or an airship has obvious VTOL capability, both are very inefficient at moving parallel to the earth's surface. The autogiro and the helicopter offer some improvement in this respect, but still have very limited performance. A large number of VTOL designs have been produced and tried. The pogo-stick, or tail-sitting, type was similar in appearance to a conventional airplane except for a special tail on which it took off and landed. This type was abandoned, partly because of the difficulty in maintaining fine control when its fuselage was positioned vertically, e.g., during a landing. Convertiplanes are VTOL craft that can fly horizontally with the same effectiveness as a conventional airplane. Some convertiplanes are conventional-looking aircraft that can tilt their rotors, or oversize propellors, so that the rotors' axes are vertical during takeoff and landing and are horizontal during forward flight. The best-known such tilt-rotor aircraft is the V-22 Osprey, which first flew in 1989. The Harrier is a jet fighter convertiplane that uses vanes to direct the thrust of its engine upward or forward and is capable of flight at approximately the speed of sound; it proved its ability to control a battlefield despite the absence of airports and runways during the 1982 Falklands conflict.

tilt-rotor aircraft: see vertical takeoff and landing aircraft.

short takeoff and landing aircraft (STOL), heavier-than-air craft, capable of rising from and descending to the ground with only a short length of runway, but incapable of doing so vertically. The precise definition of an STOL aircraft has not been universally agreed upon. However, it has been tentatively defined as an aircraft that upon taking off needs only 1,000 ft (305 m) of runway to clear a 50-ft (15-m) obstacle at the end of that distance and upon landing can clear the same obstacle and then land within 1,000 ft. Typically, STOL aircraft have large wings that are equipped with special aerodynamic devices such as slotted flaps, drooped leading edges, and auxiliary spoilers that augment lift, increase stability, and improve the effect of control surfaces. As the airfields from which STOL planes are expected to operate will be in confined areas, the ability to fly stably at low speeds, especially in turbulent air, is an important design requirement for them. See vertical takeoff and landing aircraft.

aircraft carrier, ship designed to carry aircraft and to permit takeoff and landing of planes. The carrier's distinctive features are a flat upper deck (flight deck) that functions as a takeoff and landing field, and a main deck (hangar deck) beneath the flight deck for storing and servicing the aircraft. The aircraft carrier emerged after World War I as an experimentally modified cruiser. The first aircraft carrier built (1925) from the keel up as an aircraft carrier for the U.S. navy was the U.S.S. Saratoga. The aircraft carrier remained an experimental and untested war vessel until World War II, when the Japanese destroyed or drove out of the East Asian waters the British, Dutch, and U.S. navies with carrier-borne aircraft. By 1942 the aircraft carrier had replaced the battleship as the major unit in a modern fleet, and in World War II it was indispensable in naval operations against a sea- or land-based enemy. The battle of the Coral Sea (1942) was fought by naval aircraft, and the two opposing fleets never came within gunshot range of each other. After World War II aircraft carriers were enlarged and improved by the British and U.S. navies and became the nucleus of the standard naval combat formation. With the introduction of nuclear-powered carriers in the 1960s, extremely lengthy voyages became possible because such carriers do not need regular refueling.

VTOL aircraft: see vertical takeoff and landing aircraft.

STOL aircraft: see short takeoff and landing aircraft.

Aircraft designed primarily to secure control of essential airspace by destroying enemy aircraft in combat. Designed for high speed and maneuverability, they are armed with weapons capable of striking other aircraft in flight. Developed early in World War I, they engaged in aerial combat with other fighters, shot down enemy bombers, and conducted various tactical missions. Most were biplanes with wooden frames and cloth skins, equipped with light machine guns synchronized to fire through the propeller. World War II saw the development of all-metal monoplanes that exceeded speeds of 450 mph (725 kph). Famous fighters of the period included the Focke-Wulf 190, the P-47 and P-51, and the Zero. Jet aircraft were produced at the end of the war, and jet fighters such as the U.S. Sabre and the Soviet MiG saw extensive service in the Korean War and later conflicts. Seealso air warfare, F-15, F-16.

Learn more about fighter aircraft with a free trial on Britannica.com.

Naval vessel equipped with a platform that allows airplanes to take off and land. Takeoffs are facilitated by the use of catapults or by a ramp at the end of the flight deck. For landing, aircraft are fitted with retractable hooks that engage arresting wires on the deck, or they are built with vectored-thrust engines that allow them to be landed vertically. Britain's Royal Navy developed the first true aircraft carrier near the end of World War I, and carriers played leading roles in World War II naval engagements such as the Pearl Harbor attack and the Battles of Midway and the Coral Sea. The largest modern carriers are 1,000-ft (300-m) nuclear-powered vessels of the U.S. Navy, which can carry 100 jet aircraft. Other types include the light carrier, equipped for anti-submarine warfare and ground attack, and the helicopter carrier, intended for conducting amphibious assault.

Learn more about aircraft carrier with a free trial on Britannica.com.