The Collaborative International Dictionary of English v.0.48:

Flyer \Fly"er\, n. [See Flier.]
   1. One that uses wings.
      [1913 Webster]

   2. The fly of a flag: See Fly, n., 6.
      [1913 Webster]

   3. Anything that is scattered abroad in great numbers as a
      theatrical programme, an advertising leaf, etc.
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   4. (Arch.) One in a flight of steps which are parallel to
      each other(as in ordinary stairs), as distinguished from a
      winder.
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   5. The pair of arms attached to the spindle of a spinning
      frame, over which the thread passes to the bobbin; -- so
      called from their swift revolution. See Fly, n., 11.
      [1913 Webster]

   6. The fan wheel that rotates the cap of a windmill as the
      wind veers. --Internat. Cyc.
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   7. (Stock Jobbing) A small operation not involving ?
      considerable part of one's capital, or not in the line of
      one's ordinary business; a venture. [Cant] --Bartlett.
      [1913 Webster]

WordNet (r) 3.0 (2006):

flyer
    n 1: an advertisement (usually printed on a page or in a
         leaflet) intended for wide distribution; "he mailed the
         circular to all subscribers" [syn: circular, handbill,
         bill, broadside, broadsheet, flier, flyer,
         throwaway]
    2: someone who travels by air [syn: flier, flyer]
    3: someone who operates an aircraft [syn: aviator, aeronaut,
       airman, flier, flyer]

Moby Thesaurus II by Grady Ward, 1.0:

122 Moby Thesaurus words for "flyer":
   Amtrak, Jehu, acrobat, aerialist, aeronaut, aeroplaner,
   aeroplanist, agiotage, air pilot, airplanist, arbitrage, astronaut,
   aviator, baggage train, bareback rider, barnstormer, birdman,
   buying in, cable railroad, calculated risk, captain, chance,
   choo-choo, circus artist, cloud seeder, clown, cog railroad,
   cog railway, commercial pilot, copilot, crop-duster, el, electric,
   electric train, elevated, equestrian director, equilibrist,
   equity capital, express, express train, flier, flutter, fortune,
   freight, freight train, freighter, funicular, gamble, goer,
   goods train, hazard, hell-driver, high-wire artist, horse racer,
   hummer, hustler, instructor, interurban, jet jockey, jockey,
   juggler, licensed pilot, lightning express, limited, lion tamer,
   liquidation, local, luck, metro, milk train, monorail,
   parliamentary, parliamentary train, passenger train, pilot, play,
   plunge, profit taking, racer, rack-and-pinion railroad,
   railroad train, rainmaker, rattler, ringmaster, risk,
   rolling stock, round trade, runner, scalping, scorcher, shuttle,
   shuttle train, sizzler, slack-rope artist, snake charmer, special,
   speculation, speed demon, speeder, spot sale, stepper,
   stockjobbery, stockjobbing, streamliner, stunt flier, stunt man,
   subway, sword swallower, test pilot, tightrope walker, train,
   trapeze artist, tube, tumbler, turfman, turn, uncertainty,
   underground, venture, venture capital, way train, wingman