The Collaborative International Dictionary of English v.0.48:
fast-flying \fast-flying\ adj. moving or functioning quickly and energetically; as, a fast-flying messenger. Syn: fast flying, hurrying, speedy. [WordNet 1.5]WordNet (r) 3.0 (2006):
fast-flying adj 1: moving swiftly; "fast-flying planes"; "played the difficult passage with flying fingers" [syn: fast- flying, flying]