Plane tilts back — let go! (8)
I believe the answer is:
spitfire
'plane' is the definition.
(World War 2 plane)
'tilts back let go' is the wordplay.
'tilts' becomes 'tips' ('tip' can be a synonym of 'tilt').
'back' shows that the letters should be reversed in order.
'let go' becomes 'fire' (both can mean to dismiss from a job).
'tips' written backwards gives 'spit'.
'spit'+'fire'='SPITFIRE'
(Other definitions for spitfire that I've seen before include "Famous RAF fighter" , "Quick-tempered person" , "British warplane" , "World War Two fighter aircraft" , "British fighter plane of WW2, or a fiery-tempered person" .)