Wing perhaps composed of aileron mostly (8)
I believe the answer is:
aerofoil
'wing perhaps' is the definition.
(wing is a kind of aerofoil)
'composed of aileron mostly' is the wordplay.
'composed' indicates an anagram.
'mostly' means to remove the last letter.
'of'+'aileron'='ofaileron'
'ofaileron' with its final letter taken off is 'ofailero'.
'ofailero' anagrammed gives 'AEROFOIL'.
(Other definitions for aerofoil that I've seen before include "Curved lifting surface" , "Structure offering lift" , "that may improve grip" , "Part of aircraft designed to give lift" , "Lifting section" .)