flight vs air travel

flight and air travel both are nouns.

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

As nouns, air travel is a hypernym of flight; that is, air travel is a word with a broader meaning than flight:

Other hypernyms of flight include air, aviation.

flight (noun)	air travel (noun)
an instance of traveling by air	travel via aircraft
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