air spring vs air cushion

air spring and air cushion both are nouns.

Word	Noun	Adjective	Verb	Adverb
air spring	Yes	No	No	No
air cushion	Yes	No	No	No

As nouns, air spring and air cushion are synonyms defined as:

air spring and air cushion: a mechanical device using confined air to absorb the shock of motion

air spring (noun)	air cushion (noun)
a mechanical device using confined air to absorb the shock of motion	a cushion usually made of rubber or plastic that can be inflated
	a mechanical device using confined air to absorb the shock of motion
	the trapped air that supports a hovercraft a short distance above the water or ground