pontoon plane vs hydroplane

pontoon plane and hydroplane both are nouns.

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

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

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

Other hypernyms of pontoon plane include seaplane.

pontoon plane (noun)	hydroplane (noun)
a seaplane equipped with pontoons for landing or taking off from water	an airplane that can land on or take off from water
	a speedboat that is equipped with winglike structures that lift it so that it skims the water at high speeds

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