Source : Webster's Revised Unabridged Dictionary (1913)

Air hole \Air hole\ (A["e]ronautics)
   A local region in the atmosphere having a downward movement
   and offering less than normal support for the sustaining
   surfaces of a flying machine.

Air hole \Air" hole`\ (h[=o]l`).
   1. A hole to admit or discharge air; specifically, a spot in
      the ice not frozen over.

   2. (Founding) A fault in a casting, produced by a bubble of
      air; a blowhole.

Source : WordNet®

air hole
     n 1: a local region of low pressure or descending air that causes
          a plane to lose height suddenly [syn: {air pocket}, {pocket}]
     2: a hole that allows the passage of air