Messenger taking the aerial route? (7,6)
I believe the answer is:
carrier pigeon
'messenger taking the aerial route?' is the definition.
(messenger flying through air)
'messenger taking' is the wordplay.
I cannot quite see how this works, but
'taking' could be 'on' (eg one taking drugs is 'on' drugs) and 'on' is located in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for carrier pigeon that I've seen before include "Bird with message" , "Aerial messenger" , "Bird taking messages" , "Bird used for communication" , "Messenger bird" .)