Aeronautics is the science of designing and operating aircraft, and it involves the study of FLYING and FLIGHT. It is closely related to the field of AVIATION, which is the operation of aircraft for transportation or recreation. Aeronautics includes the design, construction, and maintenance of aircraft, as well as the study of the principles of FLIGHT. The two main components of aeronautics are FLYING and FLIGHT, which are both activities that involve the use of aircraft.