By way of being a bit of an aviator (3)
I believe the answer is:
via
'by way of' is the definition.
(via means by way of or by means of)
'a bit of an aviator' is the wordplay.
'a bit of' indicates the answer is hidden within the clue.
'VIA' is hidden within '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" .)