Longman Dictionary of Contemporary English
air ambulance
noun
EXAMPLES FROM CORPUS
▪ An air ambulance service looks set to be scrapped tomorrow.
▪ Deborah Green, 28, a passenger, was taken to the hospital by air ambulance, suffering from back injuries.
▪ They also keep their aircraft busy with training, rental, business charters, air ambulance flights, aerial photography and so on.
▪ We genuinely believe there is a place for an air ambulance in those crucial incidents where an air ambulance could be vital.
▪ Where necessary, the use of a specially equipped air ambulance will be provided.
Wiktionary
air ambulance
n. An aircraft (especially a form of helicopter) equipped as an ambulance
Usage examples of "air ambulance".
THE PILOT Of the air ambulance would not go into the short, uncontrolled airfield at Arbatax in darkness.
Haynes earlier this afternoon and we've made arrangements to have Mother flown up by air ambulance.
Usual procedure is to call an air ambulance service to transport the body to the mainland.