The Collaborative International Dictionary of English v.0.48:

Ballooning spider \Bal*loon"ing spi"der\ (Zool.)
   A spider which has the habit of rising into the air. Many
   kinds (esp. species of Lycosa) do this while young by
   ejecting threads of silk until the force of the wind upon
   them carries the spider aloft.
   [1913 Webster]