ground crew vs crew

ground crew and crew both are nouns.

Word	Noun	Adjective	Verb	Adverb
ground crew	Yes	No	No	No
crew	Yes	No	Yes	No

As nouns, crew is a hypernym of ground crew; that is, crew is a word with a broader meaning than ground crew:

ground crew: the crew of technicians and mechanics who service aircraft on the ground
crew: an organized group of workmen

Other hypernyms of ground crew include gang, work party.

ground crew (noun)	crew (noun)
the crew of technicians and mechanics who service aircraft on the ground	an organized group of workmen
	the men and women who man a vehicle (ship, aircraft, etc.)
	the team of men or women manning a racing shell
	an informal body of friends

ground crew (verb)	crew (verb)
	serve as a crew member on