The sound of wings? (6,3)
I believe the answer is:
noises off
'wings?' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'the sound of' is the wordplay.
I cannot quite see how this works, but
'sound' could be 'noise' (a noise is a sound) and 'noise' is present in the answer.
'of' could be 'o' and 'o' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for noises off that I've seen before include "Stage direction" , "Direction of play" .)