The Collaborative International Dictionary of English v.0.48:

Flotilla \Flo*til"la\, n. [Sp. flotilla, dim. of flota fleet;
   akin to F. flotte, It. flotta, and F. flot wave, fr. L.
   fluctus, but prob. influenced by words akin to E. float. See
   Fluctuate, and cf. Float, n.]
   A little fleet, or a fleet of small vessels. Flotsam

WordNet (r) 3.0 (2006):

flotilla
    n 1: a United States Navy fleet consisting of two or more
         squadrons of small warships
    2: a fleet of small craft