Much about future leader is up in the air (5)
I believe the answer is:
aloft
'up in the air' is the definition.
(I've seen this before)
'much about future leader' is the wordplay.
'much' becomes 'alot' ('a lot' can be a synonym of 'much'**).
'about' indicates putting letters inside.
'leader' says to take the initial letters.
The first letter of 'future' is 'f'.
'alot' enclosing 'f' is 'ALOFT'.
'is' acts as a link.
(Other definitions for aloft that I've seen before include "Animistic cult" , "Heading for heaven" , "Up in the air, high above" , "In the air, overhead" , "To great height" .)