Undecided as to where planes go (2,2,3,3)
I believe the answer is:
up in the air
'undecided' is the definition.
(I've seen this in another clue)
'as to where planes go' is the wordplay.
I cannot really understand how this works, but
'as' could be 'in' (I've seen this in other clues) and 'in' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for up in the air that I've seen before include "Where are the clouds" , "Balloonist is" , "position of hawk or dove?" , "skylarks singing here?" , "Not sure" .)