pontoon plane vs seaplane

pontoon plane and seaplane both are nouns.

Word	Noun	Adjective	Verb	Adverb
pontoon plane	Yes	No	No	No
seaplane	Yes	No	Yes	No

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

pontoon plane: a seaplane equipped with pontoons for landing or taking off from water
seaplane: an airplane that can land on or take off from water

Other hypernyms of pontoon plane include hydroplane.

pontoon plane (noun)	seaplane (noun)
a seaplane equipped with pontoons for landing or taking off from water	an airplane that can land on or take off from water

pontoon plane (verb)	seaplane (verb)
	glide on the water in a hydroplane