Fly without a co-pilot (4)
I believe the answer is:
solo
'fly without a co-pilot' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for solo that I've seen before include "Piece for one performer" , "Lone" , "By oneself" , "Unaccompanied - card game" , "(Piece performed) on one's own" .)