Day: October 3, 2024

fly•by (flī′ bī′), n., pl. -bys. Aeronautics, Aerospace the flight of a spacecraft close enough to a celestial object, as a planet, to gather scientific data. Aeronautics Also called flypast. a low-altitude flight of an aircraft for the benefit of ground observers. flyover (def. 1). Also, fly′-by′.