Too-early start for an airman (5)
I believe the answer is:
flier
'for an airman' is the definition.
('flier' can be a synonym of 'airman')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for flier that I've seen before include "Turkey perhaps?" , "Circular" , "Advertisement" , "Good start" , "Aviator" .)