He makes one leave the air terminal (4)
I believe the answer is:
igor
'he' is the definition.
'one leave the air terminal' is the wordplay.
'one' becomes 'i' (Roman numeral).
'leave' becomes 'go' (to go is to depart or leave).
'terminal' suggests the final letters (the final or terminal letter).
The final letter of 'air' is 'r'.
'i'+'go'+'r'='IGOR'
'makes' is the link.
(Other definitions for igor that I've seen before include "Hero of Borodin" , "Prince of grand opera" , "Stravinsky, perhaps" , "Prince in Borodin's opera" , "Stravinsky, for example" .)