It's illuminating, in a way, during flight (8)
I believe the answer is:
fanlight
'it's illuminating' is the definition.
I can't tell whether this definition defines the answer.
'a way during flight' is the wordplay.
'way' becomes 'n' (Compass direction - North).
'during' means one lot of letters goes inside another.
'a'+'n'='an'
'an' placed into 'flight' is 'FANLIGHT'.
'in' is the link.
Can you help me to learn more?
(Other definitions for fanlight that I've seen before include "Rectangular window over a door" , "Small window" , "Windows above a door" , "It enables us to see" , "elevated aperture" .)