early 15c., replacing forms from Old English fleogende "flying, winged;" present participle adjective from fly (v.1). The meaning "attached so as to have freedom of movement" (1670s) is the source of the nautical use (flying jib, etc.). Meaning "designed for rapid movement" (especially in military terms) is from 1660s; meaning "passing, hasty, temporary, rapidly constructed" is from 1763.
Flying fish is from 1510s; flying buttress is from 1660s. Flying Dutchman, ghost ship off the Cape of Good Hope, is attested since 1803 [John Leyden, "Scenes of Infancy," who describes it as "a common superstition of mariners"]. Flying colors (1706) probably is from the image of a naval vessel with the national flag bravely displayed. Flying machine is from 1736 as a theoretical device. Flying saucer first attested 1947, though the image of saucers for unidentified flying objects is from at least 1880s.
