Postpone work on missile attached to plane (8)
I believe the answer is:
mothball
'postpone work' is the definition.
(I've seen this before)
'missile attached to plane' is the wordplay.
'missile' becomes 'ball' (ball is a kind of missile).
'attached to' says to put letters next to each other.
'plane' becomes 'moth' (Tiger Moth is an example).
'ball' after 'moth' is 'MOTHBALL'.
'on' is the link.
(Other definitions for mothball that I've seen before include "Put under wraps" , "Postpone work" , "Lay aside indefinitely" , "put on back burner" , "Put on ice" .)