The Collaborative International Dictionary of English v.0.48:

Flyaway \Fly"a*way`\, a.
   Disposed to fly away; flighty; unrestrained; light and free;
   -- used of both persons and things. -- n. A flyaway person or
   thing. "Truth is such a flyaway." --Emerson.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

flyaway
    adj 1: guided by whim and fancy; "flighty young girls" [syn:
           flighty, flyaway, head-in-the-clouds,
           scatterbrained]
    2: (of hair or clothing) worn loose; "her flyaway hair"; "a
       flyaway coat"