Studio sign (5)
'studio sign' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for on air that I've seen before include "Cushioned" , "In the process of broadcasting - floating aloft?" , "In the process of broadcasting on radio or TV" , "Live broadcast" , "Radio show might be" .)
'studio sign' is the definition.
(I've seen this in another clue)
This is all the clue.