By way of being a bit of an aviator (3)
I believe the answer is:
via
'by way of' is the definition.
(thesaurus)
'a bit of an aviator' is the wordplay.
'a bit of' indicates a hidden word (I've seen 'a bit' mean this (the answer is formed by a bit of the clue)).
'VIA' can be found hidden inside 'aviator'.
'being' acts as a link.
(Other definitions for via that I've seen before include "A Roman way" , "By means of" , "Roman road" , "By way of - in Latin" , "Passing through" .)