The word airplanes is a noun. It is the plural of airplane.
We can find airplanes in the airport
airplanes
the engine
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
Well, there are some airplanes which can be outrun by helicopters, but, for the most part, airplanes are faster.
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.