air travel vs flight

air travel and flight both are nouns.

Word	Noun	Adjective	Verb	Adverb
air travel	Yes	No	No	No
flight	Yes	No	Yes	No

As nouns, flight is a hyponym of air travel; that is, flight is a word with a more specific, narrower meaning than air travel:

Other hyponyms of air travel include flying.

air travel (noun)	flight (noun)
travel via aircraft	an instance of traveling by air
	the act of escaping physically
	a scheduled trip by plane between designated airports
	a stairway (set of steps) between one floor or landing and the next
	passing above and beyond ordinary bounds
	an air force unit smaller than a squadron
	a formation of aircraft in flight
	a flock of flying birds
	the path followed by an object moving through space