Flying not decided (2,3,3)
I believe the answer is:
in the air
'flying' is the definition.
(I've seen this before)
'not decided' is the wordplay.
I cannot quite understand how this works, but
'not' could be 'nt' (synonyms) and 'nt' 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 in the air that I've seen before include "How one might describe song's contents" , "Unsettled" , "travelling on a jumbo?" , "Undecided; current" , "Place for a lark" .)