Russian fighter in a hole needs friend (5)
I believe the answer is:
amigo
'friend' is the definition.
('friend' in Spanish)
'russian fighter in a hole' is the wordplay.
'russian fighter' becomes 'MiG' (Russian fighter plane manufacturer).
'in' is an insertion indicator.
'hole' becomes 'O'.
'a'+'o'='ao'
'mig' going within 'ao' is 'AMIGO'.
'needs' acts as a link.
(Other definitions for amigo that I've seen before include "Mexican friend" , "A Spanish pal" , "Pal from Madrid?" , "Hispanic comrade" , "Friend in Spanish-speaking area" .)