Plane perhaps in flight, re-examined (4)
I believe the answer is:
tree
'plane perhaps' is the definition.
(I've seen this before)
'in flight re-examined' is the wordplay.
'in' says the answer is hidden in the clue.
'TREE' is hidden within 'flight re examined'.
(Other definitions for tree that I've seen before include "Beech, for example" , "Plane possibly" , "Be up a .... to be in difficulties" , "Elm, perhaps" , "Christmas decoration" .)