The importance of aircraft designed specifically for use by the military was recognized within a decade of the initial controlled, power-driven airplane flights achieved by Orville and Wilbur Wright on Dec. 17, 1903. Although zeppelins had been flown since 1900--and more than 100 were built by Germany for use in World War I (see \Tairship\t)--the smaller, faster, more maneuverable airplane quickly proved superior for warfare, and it is today the principal weapon of military attack and defense. (See \Taircraft\t and \Taviation\t for the technology and development of planes. For the development of independent military air units, see \Tair force\t.) TYPES OF MILITARY AIRCRAFT The military aircraft's original function was large-scale reconnaissance. A scout plane equipped with bombs proved to be a weapon of unprecedented destructive potential; inevitably, the use of bomber aircraft led to the development of the fighter, an airplane capable of intercepting and destroying bombers. In addition to its use above the battlefield, the fighter was used extensively against enemy aircraft for home defense, as a protective escort for bombers, and as a strike plane against such objectives as enemy airports and railroads. The introduction of the airplane provided a \Ttorpedo\t-launching device with several advantages over ships, particularly in speed of approach to a target. Torpedo-dropping experiments commenced early in the development of aircraft and were soon followed by the production of specialized torpedo-bombers. Mine-laying aircraft were used to inhibit enemy ship movements, and during World War II the airplane was also adapted to counter the magnetic mine by exploding it electronically in the water after locating it. Between the wars increasing attention was paid to the development of transport aircraft, in particular for the landing of troops and equipment and for the deployment of both soldiers and arms by \Tparachute\t (see \Tairborne troops\t). For a short time during World War II, \Lglider\ls were also used extensively. They were towed to their destination and then released to land with their cargoes. Since 1945, development has been concentrated on the \Thelicopter\t as a transport vehicle, because it can take off and land vertically and can hover to provide support for ground troops. As early as 1942 the helicopter was also being tested as a combat craft, and it has now been developed into a strike aircraft heavily armed with cannon, machine guns, rockets, torpedoes, and a variety of powerful missiles. It can be equipped to operate as an antisubmarine weapon as well. The outstanding success of the fighter in strike missions during World War II was responsible for the production after the war of an entirely new class of airplane, the attack aircraft, designed specifically for close support and strike functions but also able to intercept. Emphasis in an attack aircraft is on flexibility and on bomb transport and targeting capacity, coupled with the ability to fly at low altitudes to evade \Tradar\t detection, ground fire, and ground-to-air missiles. The counterinsurgency (\Tcoin\t) aircraft has emerged as a distinct class of warplane since World War II, serving as a comparatively lightweight, low-cost, and simple strike plane for close support of ground forces in relatively elementary tactical operations. In many cases obsolescent strike and trainer planes have been adapted to serve as \Tcoin\t aircraft. The serious threat to a nation's shipping posed by fleets of advanced nuclear submarines requires the maintenance of strong maritime patrol forces and antisubmarine aircraft. With long ranges and advanced equipment and weapons, these types of aircraft have assumed a role of the utmost significance since 1945. The need for immediate warning of approaching hostile aircraft has led to the development of extremely sophisticated airplanes capable of extended patrol missions. A plane equipped with an \TAirborne Warning and Control System\t (\TAWACS\t) is vastly more effective, and has much greater range, than a similar system based on the ground or at sea. Training aircraft have also assumed a vital role, and specialized airplanes have been developed to train crews for all categories of operational aircraft. Many of these training planes can be converted quickly into warplanes. HISTORY The U.S. Army was the first armed service to acquire an airplane. On Dec. 23, 1907, Brig. Gen. James Allen, the chief signal officer, issued a specification for a military aircraft, and a contract was placed with the Wright brothers on Feb. 10, 1908. Italy was the first country to use an airplane in war. On Oct. 23, 1911, during the Italo-Turkish War in North Africa, a plane was employed for reconnaissance. Soon after, Italian airplanes dropped bombs and propaganda leaflets and photographed enemy positions. World War I By the beginning of World War I, little progress had been made by the belligerents in formulating distinct policies for the use of aircraft. Military airplanes were unarmed and were used primarily for visual and photographic reconnaissance over enemy lines. The opposing sides were quick to develop armament to protect their scouting aircraft from ground fire, and such armed aircraft were soon developed into fighter planes that could be used to intercept roving reconnaissance planes. The latter, in turn, acquired escort fighters for their own protection. Combat between fighters began, and it continued with formations of increasing size until the Armistice. Early in the war, bombing raids were made against the bases that sheltered German zeppelins which had been used in bomb attacks against Britain; specialized bombing airplanes were developed subsequently. By 1915 the value of the airplane in war had been recognized fully, and design, development, and production of aircraft were given the highest priority. The wood-and-fabric biplane predominated, but military forces also developed monoplanes and triplanes, with single, twin, and multiple engines of rotary, radial, and in-line types, both air-cooled and water-cooled. The synchronization of machine-gun fire through the propeller arc without hitting the blades and the evolution of bombsights proved of extreme importance, and many technical advances were made in airplanes themselves. Particular emphasis was laid on increasing speed, height, range, and load-carrying capacity, and during World War I the airplane evolved into a highly effective weapon. Its potential was confirmed on Apr. 1, 1918, with the formation of Britain's Royal Air Force (RAF), the world's first independent air service. On June 6, 1918, the Independent Force was constituted within the RAF for the strategic bombing of the German munitions industry. Between the Wars Although the Armistice on Nov. 11, 1918, brought immediate disarmament and attendant financial constraint, the war had been a strong stimulus to the development of military and naval aircraft. Nations able to retain air services encouraged their designers of airplanes, engines, and armaments to produce improved equipment. Three prominent advocates of air power were the U.S. brigadier general Billy \TMitchell\t, the British general Hugh Montague Trenchard, and the Italian general Giulio Douhet, whose Command of the Air (1921) set forth theories--held in common by all three--that were to form the basis for the future development of military air power. Essentially, these theorists believed that the first function of an air force was to carry the attack beyond the battlefield into the heart of enemy country, to destroy the industries that support the opposing armies, and to sap the will of the civilian population. The biplane remained dominant for naval use until the 1930s. U.S. government sponsorship of monoplane designs, however, exerted such a great influence on airframe design and related engine, propeller, and fuel developments that the monoplane eventually became the only type able to meet the incessant demand for increased aircraft performance. Significant innovations adopted during this period included retractable landing gear, flaps, the variable-pitch propeller, and the supercharger. The wars in Ethiopia, Spain, and China during the 1930s enabled the Germans, Italians, Russians, and Japanese to evaluate their new warplanes under battle conditions. World War II Before the outbreak of World War II, each belligerent had equipped and trained its air arms to fulfill specific, clearly defined functions. In accordance with the prophetic doctrines of Mitchell, Trenchard, and Douhet, the United States, Great Britain, and Italy had concentrated particularly on developing the long-range strategic bomber. Germany, the \TUSSR\t, and Japan, however, had built air forces designed expressly to support army operations. Additionally, the United States and Japan had supplied their navies with airplanes of the dive-bombing type. Being an island power, Japan had stressed the requirement that its navy be adequately equipped with torpedo bombers for action against enemy ships. During the action in Europe, the British Isles served as the main base for Allied strategic bombing operations against the Axis, with the U.S. Army Air Force engaged primarily in daylight attacks and the RAF conducting night raids. The \Taircraft carrier\t demonstrated its worth in highly specialized actions in the war in the Pacific. Radar quickly assumed a role of paramount importance in detecting approaching raiders and as a navigational and bombing aid. Newly developed airplanes were equipped with advanced armament and weapons, including new types of bombs, heavy-caliber cannon, and rocket projectiles. Rocket-propelled fighters were introduced by the Germans, and the Japanese used Kamikaze (suicide) aircraft in attacking Allied ships. Two innovations, however, transcended all others: the turbojet engine and the \Tatomic bomb\t. The first operational jet-propelled aircraft, and the only one of its type to see significant action in World War II, was Germany's Messerschmitt Me 262. About a year later, atomic bombs were dropped by the U.S. Army Air Force on Hiroshima (Aug. 6, 1945) and on Nagasaki (Aug. 9, 1945), bringing World War II to an end on Aug. 14, 1945. After World War II A new generation of advanced bombers with unprecedented range and speed was developed to serve as vehicles for nuclear bombs, for conventional bombs, and for missiles. (Much of the engineering for this new generation of bombers was based on highly advanced German research carried out during World War II.) The jet engine and rocket propulsion were developed further, along with numerous exterior design innovations, notably delta and swept-back wings. To enable airplanes to remain airborne for extended periods, refueling in flight from tanker aircraft evolved. The development of all categories of airplanes and associated weapons was accelerated by the Berlin Airlift and by the outbreak of wars in the Middle East, Korea, and Vietnam. Supersonic flight was achieved and eventually became a necessity in the performance of fighters and bombers. The high speed of jet aircraft necessitated the development of a high-speed method of abandoning a plane in an emergency. The ejection seat, first tried in 1946, uses an explosive charge to catapult the entire seat unit clear of the plane. A parachute then opens automatically, floating the crew member to a safe landing. A significant advance in fixed-wing aircraft design was the vertical takeoff and landing craft (see \TVTOL\t), a British accomplishment that produced a fighter aircraft with reconnaissance and strike functions. In armament, the machine gun and cannon were augmented by the rapid-fire multibarrel cannon and an extensive array of guided \Lmissile\ls. The dramatic increase in performance engendered by the jet engine was made possible by the concurrent development of a wide range of new materials for airframe construction, including light metal alloys, plastics, fiberglass, and carbon-fiber. NEW TECHNOLOGIES The most significant recent advances in military aviation technology have been made in the area of flight guidance and control--both of the planes themselves and their weaponry. The pilotless plane, or drone, is a prime example. One of the first drones, the Firebee (originally produced in 1959), is launched and controlled from the ground or a plane; or, when fitted with a computer, it is capable of following a preset course and returning. The present-day Firebee can fly at altitudes of up to 18,250 m (60,000 ft) at speeds approaching 800 km/h (500 mph). It is usually equipped with radar and camera systems and functions as a reconnaissance craft. The U.S. Army is currently developing a 68-kg (150-lb) drone, the Aquila, that in addition to performing reconnaissance duties will also be capable of directing laser-guided missiles. The technologies used in advanced drones-- sophisticated radar systems that are capable of ground mapping, laser inertial navigation, computers that can control and target weapons systems--are also used in piloted military aircraft, which supplement these systems with sophisticated electronic display panels. The V/STOL plane is capable of taking off and landing either vertically or on very short runways. Some new craft are Some new craft are hybrid mixtures of helicopters and conventional airplanes, whose wings carry large-bladed propellers that can be rotated parallel to the wing to lift the vehicle, or moved forward to allow it to cruise like a plane. Important advances have also been made in the area of \Tradar\t avoidance. The materials and design used to construct the F-117A \Tstealth fighter\t and the \TStealth bomber\t render them immune to detection by conventional radar. Peter M. H. Lewis Bibliography: Bruce, J. M., War Planes of the First World War, 5 vols. (1969-72); Campbell, C., Air Warfare (1985); Ekmory, J. M., Source Book of World War II Aircraft (1987); Franks, N., Aircraft vs. Aircraft (1986); Green, W., Warplanes of the Third Reich (1970); Gunston, Bill, An Illustrated Guide to modern Fighters and Attack Aircraft, rev. updated ed. (1987); Jackson, Robert, World Military Aircraft Since 1945 (1980); Jane's All the World's Aircraft (annual); Lewis, Peter, The British Fighter since 1912 (1974) and The British Bomber since 1914 (1974) and The British Fighter since 1912 (1974); Polmar, Norman, and Kennedy, Floyd, Military Helicopters of the World (1981); Wagner, William, Lightning Bugs and Other Reconnaissance Drones (1982); Waters, Andrew W., All the United States Air Force's Airplanes, 1907-80 (1982). See also: B-1 \Lbomb\ler; B-17 \Tflying\t FORTRESS; B-24 \Lliberat\lor; B-29 SUPERFORTRESS; B-52 STRATOFORTRESS; \TCorsair\t; F-16 \Tflying\t \Tfalcon\t; F-86 SABRE; \TFokker D-VII\t; \TGotha\t (aircraft); \TGrumman TBF-1 Avenger\t; \THurricane\t; \TMesserschmitt Bf\t-109; \TMiG\t; \TMirage\t; \TMosquito\t; \TMustang\t; P-38 \Tlightning\t; P-40; \TSopwith Camel\t; \TSPAD\t; \TSpitfire\t; \TStuka\t; U-2; \TZero\t.