Airman changing into girl (6)
I believe the answer is:
marina
'girl' is the definition.
'airman changing' is the wordplay.
'changing' indicates an anagram.
'airman' anagrammed gives 'MARINA'.
'into' is the link.
(Other definitions for marina that I've seen before include "Docking place for pleasure craft" , "Yacht station" , "Place for mooring boats" , "Docking facility for pleasure craft" , "Pleasure-boat dock" .)