Flight operator allowing diver to breathe? (7)
I believe the answer is:
airline
'flight' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for airline that I've seen before include "SAS, say" , "Qantas, for example" , "It serves both divers and travellers" , "Business taking off" , "It creates inflation" .)