The Collaborative International Dictionary of English v.0.48:

Flyer \Fly"er\, n. [See Flier.]
   1. One that uses wings.
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   2. The fly of a flag: See Fly, n., 6.
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   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.
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   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.
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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]