One opposed to war in the air? (4)
I believe the answer is:
dove
This clue might be a double definition.
'one opposed to war' is the first definition.
(dove can mean someone favouring peace)
'air?' is the second definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'in the' is the link.
Can you help me to learn more?
(Other definitions for dove that I've seen before include "So-called pacifist" , "Bird in the pigeon family" , "Bird representing peace" , "Mourning, collared, bird" , "Peace lover; bird" .)