The Collaborative International Dictionary of English v.0.48:

Aerostation \A`["e]r*os*ta"tion\, n. [Cf. F. a['e]rostation the
   art of using a["e]rostats.]
   1. That part of a["e]ronautics that deals with passive
      balloons; the art of raising and guiding balloons in the
      air.
      [1913 Webster +Webster 1913 Suppl.]

   2. The science of weighing air; a["e]rostatics. [Obs.]
      [1913 Webster]