tanker plane vs airplane

tanker plane and airplane both are nouns.

Word	Noun	Adjective	Verb	Adverb
tanker plane	Yes	No	No	No
airplane	Yes	No	No	No

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

tanker plane: an airplane constructed to transport chemicals that can be dropped in order to fight a forest fire
airplane: an aircraft that has a fixed wing and is powered by propellers or jets

Other hypernyms of tanker plane include aeroplane, plane.

tanker plane (noun)	airplane (noun)
an airplane constructed to transport chemicals that can be dropped in order to fight a forest fire	an aircraft that has a fixed wing and is powered by propellers or jets