test pilot vs airplane pilot

test pilot and airplane pilot both are nouns.

Word	Noun	Adjective	Verb	Adverb
test pilot	Yes	No	No	No
airplane pilot	Yes	No	No	No

As nouns, airplane pilot is a hypernym of test pilot; that is, airplane pilot is a word with a broader meaning than test pilot:

test pilot: a pilot hired to fly experimental airplanes through maneuvers designed to test them
airplane pilot: someone who is licensed to operate an aircraft in flight

Other hypernyms of test pilot include pilot.

test pilot (noun)	airplane pilot (noun)
a pilot hired to fly experimental airplanes through maneuvers designed to test them	someone who is licensed to operate an aircraft in flight