Lift to reveal flaps (8)
I believe the answer is:
elevator
'lift' is the definition.
(synonyms)
'to reveal flaps' is the wordplay.
'flaps' is an anagram indicator (I've seen 'flapping' mean this (flap can mean to move or fly around)).
'to'+'reveal'='toreveal'
'toreveal' with letters rearranged gives 'ELEVATOR'.
(Other definitions for elevator that I've seen before include "US lift" , "what makes flight unnecessary" , "Gentle caress" , "may give you a lift" , "An American lift in building" .)