Auster was I think a military designation, and like a lot of English military aircraft (Tempest, Typhoon, Hurricane, Tornado etc) , it was named after a wind.
Auster is a Roman word for a light breeze.
I dissent, however, in the use of the term "light"...since when was an Auster "light"?
Aiglet I believe is an aviary term (bird) as in "Harrier, Hunter, Gnat, Arrow, Swallow" etc.
But I'm not sure.
DT