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

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "flotilla":
   Naval Construction Battalion, RN, Royal Navy, Seabees, USN,
   United States Navy, argosy, armada, bottoms, coast guard, division,
   escadrille, fleet, line, marine, merchant fleet, merchant marine,
   merchant navy, mosquito fleet, naval forces, naval militia,
   naval reserve, navy, shipping, ships, squadron, task force,
   task group, tonnage, whaling fleet