(countable, aviation) An act of flight. / (uncountable, aerodynamics) The action or process of sustained motion through the air.

(of airspace) In which aircraft are forbidden to fly. / (of people) Who are forbidden to board an aircraft.

(baseball, of the ball) While in the air, without having touched the ground. / (idiomatic) Spontaneously or extemporaneously; done as one goes, or during another activity.

(aviation) An informal gathering of private pilots and their aircraft at a prearranged airfield.

Alternative spelling of on the fly

plural of flying

Used other than figuratively or idiomatically: see fly, by. / (idiomatic) To pass or go past quickly, often without much interaction

present participle of fly by

A surname.

Alternative form of flyby