any machine capable of flying by means of buoyancy or aerodynamic forces, such as a glider, helicopter, or aeroplane
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
Any structure, machine, or contrivance, especially a vehicle, designed to be supported by the air, either by the dynamic action of the air upon the surfaces of the structure or object or by its own buoyancy. Also known as air vehicle.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
Any vehicle which carries one or more persons and which navigates through the air. The two main classifications of aircraft are lighter-than-air and heavier-than-air. The term lighter-than-air is applied to all aircraft which sustain their weight by displacing an equal weight of air, for example, blimps and dirigibles. Heavier-than-air craft are supported by giving the surrounding air a momentum in the downward direction equal to the weight of the aircraft. See Airplane, Helicopter
McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.
Any structure, vehicle, or machine designed to travel through air supported by its own buoyancy or by the action of air on its surfaces. It includes airplanes, gliders, helicopters, and balloons. It does not include hovercraft, which obtain their lift from the reaction of air against the earth's surface. ICAO defines aircraft as “any machine that can derive support in the atmosphere from the reaction of the air other than the reaction of the air against the earth's surface.” Aircraft has also been defined as “device(s) that are used or intended to be used for flight in the air, and when used in air traffic control terminology, may include the flight crew” (“AIM,” FAA).
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved