operation of heavier-than-air aircraft and related activities. Aviation can be conveniently divided into military aviation, air transport, and general aviation. Military aviation includes all aviation activity by the armed services, such as combat, reconnaissance, and military air transport. Air transport consists mainly of the operation of commercial airlines, which handle both freight and passengers. General aviation consists of agricultural, business, charter, instructional, and pleasure flying; it includes such activities as the operation of air taxis, as well as aerial surveying and mapping.
See also air, law of the; air navigation; airplane; airship.
Interest in aviation can be traced back as far as Leonardo da Vinci; a human-powered aircraft based in part on his designs, Daedalus 88, flew 72 mi (115 km) in 1988. However, real progress toward achieving flight in heavier-than-air machines only began in the middle of the 19th cent. In 1842 the Englishman W. S. Henson patented a design for a machine that closely foreshadowed the modern monoplane; another Englishman, John Stringfellow, developed a model plane said to be the first power-driven machine to fly; and a third Englishman, F. H. Wenham, devised the first wind-tunnel experiments. In France, Alphonse Penaud made successful flying models of airplanes, while Clément Ader actually achieved flight (over a distance of about 150 ft/45 m in 1890 and about 300 yd/280 m in 1897) in a power-driven monoplane fashioned after a bat. In 1894 a plane built in England by Sir Hiram S. Maxim, operated by steam engines and carrying a crew of three, rose into the air from the track on which it was being tested. In the United States, S. P. Langley, Octave Chanute, and Otto Lilienthal made notable contributions to the early development of the airplane.
Finally, on Dec. 17, 1903, Orville and Wilbur Wright flew the first piloted airplane off the beach near Kitty Hawk, N. C. Henri Blériot and Glenn H. Curtiss made significant improvements in airplane design and, as more powerful engines became available, flew successively longer distances. In 1909 Blériot flew across the English Channel; ten years later a Curtiss-designed flying boat crossed the Atlantic Ocean. At first aviation development was motivated by the large prizes put up by publicity-seeking newspapers; but the outbreak of World War I in 1914 provided far greater motivation for aviation research and development (see air forces. The cessation of hostilities made available a large number of aircraft that could be bought cheaply, and the result was a great deal of aviation activity; barnstorming and stunt-flying kept aviation before the eyes of the public for a time, but the real stimulus was the initiation of airmail service in the mid-1920s. The intrepid airmail pilots caught the fancy of the public, and out of this group came the famous solo fliers Lindbergh, St-Exupéry, and others.
During the 1930s aviation continued to expand. Technological improvements in wind-tunnel testing, engine and airframe design, and maintenance equipment combined to provide faster, larger, and more durable airplanes. The transportation of passengers became profitable, and routes were extended to include several foreign countries. TransPacific airmail service, begun by Pan American Airways (later Pan American World Airways) in 1934, was followed by the first transoceanic aviation service for passengers, on the China Clipper, from San Francisco to Manila (to Hong Kong in 1937). In 1939 the first transatlantic service carrying both mail and passengers was inaugurated.
The outbreak of World War II interrupted commercial air service, but by 1947 all the basic technology essential to contemporary aviation had been developed: jet propulsion, streamlining, radar, and metallurgy. Perhaps the greatest example of this transition from military technology to commercial applications is the Boeing Company, a minor military contractor which became the largest aircraft manufacturer in the world. Commercial jet transportation began in 1952, when the British Overseas Airways Comet first flew from London to Johannesburg. Though this service was short-lived, by 1960 several commercial jet aircraft were in service; today virtually all commercial air routes are flown by jet or turboprop aircraft. The latest significant development in aviation has been the introduction of fly-by-wire control systems, which rely on computers and electronics rather than cables to operate aircraft control surfaces.
The result has been the explosive growth of commercial aviation, from jumbo and superjumbo jetliners to overnight package services, while general aviation has lagged behind. This growth has not been without some major problems. Jet aircraft use more fuel and require longer runways and more durable construction materials, and their sheer numbers create special problems for air-traffic control. In addition, the takeoff and landing of jet aircraft over populated areas create locally dangerous levels of noise pollution.