<P> An aircraft is a machine that is able to fly by gaining support from the air . It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines . Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, and hot air balloons . </P> <P> The human activity that surrounds aircraft is called aviation . Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self - controlled by onboard computers . Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others . </P>

The three crafts normally associated with an air