It's on the wing (7)
I believe the answer is:
aileron
'wing' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'it's on' is the wordplay.
'it's' becomes 'ailer' (I am not sure about this - if you are sure you should believe this answer much more).
'ailer'+'on'='AILERON'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for aileron that I've seen before include "Wing control flap" , "Movable part of an airplane wing" , "Movable part of an aircraft's wing" , "Moveable part of aircraft wing" , "Aircraft's wing foil that controls lateral motion" .)