Aviation

Aviation most often refers to the development and operation of heavier-than-air aircraft. It includes civil aviation—the nonmilitary use of aircraft—and military aviation. Civil aviation ranges from scheduled passenger and cargo services to general aviation, a broad group of non-commercial flights that includes recreation, business travel and specialized work such as agriculture or humanitarian support. Aircraft also differ in how they generate lift and are controlled: conventional airplanes use fixed wings, while helicopters and other rotorcraft use rotating blades. Balloons and other lighter-than-air craft have a separate but closely connected history of human flight.

For an airplane in flight, four forces are central: lift, weight, thrust and drag. Lift is produced by airflow around the wings; weight is the downward force of gravity; thrust is supplied by an engine and propeller or by a jet; and drag resists motion through the air. In steady, level flight, lift balances weight and thrust balances drag. Pilots and automated controls alter the aircraft's attitude and control surfaces to change direction or altitude. These principles apply differently across aircraft designs: a helicopter, for example, produces lift with rotor blades rather than fixed wings.

Human flight began with lighter-than-air balloons: the Montgolfier brothers pioneered passenger-carrying balloon flights in France in 1783. Nineteenth-century work by George Cayley and glider experiments by Otto Lilienthal helped establish the study and practice of heavier-than-air flight. On 17 December 1903, Wilbur and Orville Wright made successful powered flights in a heavier-than-air machine near Kitty Hawk, North Carolina. The achievement grew out of years of experiments with gliders, control and wind-tunnel testing. Aircraft developed quickly thereafter: military use expanded during the First World War, airlines began carrying mail in the 1920s, and jet aircraft later enabled much faster commercial travel over long distances.

Aircraft are only one part of aviation. Airports, runways, maintenance facilities, navigation systems, trained crews, air-traffic services and operating rules make regular flight possible. The sector serves passenger travel and freight, while general aviation also supports recreational and business flying, agriculture, environmental conservation and humanitarian work. National authorities oversee areas such as aircraft certification, airline safety and air-traffic management; the U.S. Federal Aviation Administration (FAA) is one example. International coordination is also essential: the International Civil Aviation Organization (ICAO), a United Nations agency established in 1944, helps countries cooperate on international civil aviation and share the use of airspace.

Aviation safety depends on several layers working together, including aircraft design and certification, maintenance, pilot and crew training, airport operations, air-traffic control and continuing oversight. These responsibilities are distributed among regulators, operators and aviation professionals rather than resting on a single safeguard. Aircraft engines also produce emissions. ICAO tracks international aviation emissions including carbon dioxide, nitrogen oxides and non-volatile particulate matter, and coordinates work on reducing climate effects. In 2022, ICAO's Assembly adopted a collective long-term aspirational goal of net-zero carbon emissions for international aviation by 2050; this is a stated global goal, not a claim that aviation has already reached it.