fighter vs airplane

fighter and airplane both are nouns.

Word	Noun	Adjective	Verb	Adverb
fighter	Yes	No	No	No
airplane	Yes	No	No	No

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

fighter: a high-speed military or naval airplane designed to destroy enemy aircraft in the air
airplane: an aircraft that has a fixed wing and is powered by propellers or jets

Other hypernyms of fighter include aeroplane, plane, military plane, warplane.

fighter (noun)	airplane (noun)
a high-speed military or naval airplane designed to destroy enemy aircraft in the air	an aircraft that has a fixed wing and is powered by propellers or jets
someone who fights (or is fighting)
someone who fights for a cause