air pocket

from WordNet (r) 3.0 (2006)

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

from The Collaborative International Dictionary of English v.0.48

Air hole \Air" hole`\ ([^a]r" h[=o]l`).
   1. A hole to admit or discharge air; specifically, a spot in
      the ice not frozen over.
      [1913 Webster]

   2. (Founding) A fault in a casting, produced by a bubble of
      air; a blowhole.
      [1913 Webster]

   3. (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, causing
      an airplane to drop suddenly. Same as {air pocket}.
      [Webster 1913 Suppl.]

from The Collaborative International Dictionary of English v.0.48

Air pocket \Air" pock"et\ (p[o^]k"[e^]t). (aeronautics)
   A local region in the atmosphere having a downward movement
   and offering less than normal support for the sustaining
   surfaces of a flying machine, causing an airplane to drop
   suddenly. Same as {air hole}.
   [PJC.]

from Moby Thesaurus II by Grady Ward, 1.0

32 Moby Thesaurus words for "air pocket":
      CAT, aerospace, aerosphere, air hole, airspace, bump, ceiling,
      crosswind, empty space, favorable wind, fog, front, head wind,
      high-pressure area, hole, ionosphere, jetstream, low-pressure area,
      overcast, pocket, roughness, soup, space, stratosphere,
      substratosphere, tail wind, tropopause, troposphere, trough,
      turbulence, visibility, visibility zero