fighter aircraft vs airplane

fighter aircraft and airplane both are nouns.

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

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

fighter aircraft: 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 aircraft include aeroplane, plane, military plane, warplane.

fighter aircraft (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