The Collaborative International Dictionary of English v.0.48:
Flee \Flee\ (fl[=e]), v. i. [imp. & p. p. Fled (fl[e^]d); p.
pr. & vb. n. Fleeing.] [OE. fleon, fleen, AS. fle['o]n
(imperf. fle['a]h); akin to D. vlieden, OHG. & OS. fliohan,
G. fliehen, Icel. fl[=y]ja (imperf. fl[=y][eth]i), Dan. flye,
Sw. fly (imperf. flydde), Goth. [thorn]liuhan. [root]84. Cf.
To run away, as from danger or evil; to avoid in an alarmed
or cowardly manner; to hasten off; -- usually with from. This
is sometimes omitted, making the verb transitive.
[He] cowardly fled, not having struck one stroke.
Flee fornication. --1 Cor. vi.
So fled his enemies my warlike father. --Shak.
Note: When great speed is to be indicated, we commonly use
fly, not flee; as, fly hence to France with the utmost
speed. "Whither shall I fly to 'scape their hands?"
--Shak. See Fly, v. i., 5.