Near end of flight in darkness (5)
I believe the answer is:
night
'darkness' is the definition.
(night is a period of darkness)
'near end of flight' is the wordplay.
'near' becomes 'nigh' (similar in meaning).
'end of' suggests the final letters.
The last letter of 'flight' is 't'.
'nigh'+'t'='NIGHT'
'in' is the link.
(Other definitions for night that I've seen before include "Ignorance" , "Dark hours" , "Darkness; see you in the morning" , "End of the day" , "Time between days" .)