"flying," O.E. flyht "a flying, flight." from P.Gmc. *flukhtiz (cf. Low Ger. flugt, Ger. Flucht). Spelling altered from M.E. fliht c. 1385 (see fight), from root of *fleugan "to fly" (see fly (v.1)). Meaning "an instance of flight" is 1785, originally of ballooning. Meaning "series of stairs between landings" is from 1703. Flighty is 1552 in sense of "swift," later (1768) "fickle or frivolous," originally of skittish horses.