pontoon plane vs floatplane

pontoon plane and floatplane both are nouns.

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

As nouns, pontoon plane and floatplane are synonyms defined as:

pontoon plane and floatplane: a seaplane equipped with pontoons for landing or taking off from water

pontoon plane (noun)	floatplane (noun)
a seaplane equipped with pontoons for landing or taking off from water	a seaplane equipped with pontoons for landing or taking off from water