Message airily taken by car (5)
I believe the answer is:
cable
'message' is the definition.
(cable is a kind of message)
'airily taken by car' is the wordplay.
'airily' becomes 'le' (I can't justify this - if you can you should believe this answer much more).
'taken by' means one lot of letters go next to another.
'car' becomes 'cab' (cab is a kind of car).
'le' after 'cab' is 'CABLE'.
Can you help me to learn more?
(Other definitions for cable that I've seen before include "Wire, flex" , "Heavy chain or rope" , "Thick wire; telegram" , "Telegram; wire rope" , "Strong line" .)