Source : Webster's Revised Unabridged Dictionary (1913)

Flyaway grass \Flyaway grass\ (Bot.)
   The hair grass ({Agrostis scabra}). So called from its light
   panicle, which is blown to great distances by the wind.

Hair grass \Hair" grass`\ (Bot.)
   A grass with very slender leaves or branches; as the
   {Agrostis scabra}, and several species of {Aira} or
   {Deschampsia}.