Not an RAF weapon, though it's built into the plane (8)
I believe the answer is:
aerofoil
'the plane' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'not an raf weapon though it's built' is the wordplay.
I cannot quite understand how this works, but
'not' could be 'o' (I've seen this in other clues) and 'o' is present in the answer.
'an' could be 'i' (Roman numeral for one) and 'i' is found within the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
an anagram of 'raf' is 'arf' which is located in the remaining letters.
This may be the basis of the clue (or it may be nonsense).
'into' acts as a link.
Can you help me to learn more?
(Other definitions for aerofoil that I've seen before include "Curved lifting surface" , "Structure offering lift" , "that may improve grip" , "Lifting section" , "Loire oaf (anag.)" .)