air cushion vs air spring

air cushion and air spring both are nouns.

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

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

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

air cushion (noun)	air spring (noun)
a cushion usually made of rubber or plastic that can be inflated	a mechanical device using confined air to absorb the shock of motion
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