airsickness vs air sickness

airsickness and air sickness both are nouns.

Word	Noun	Adjective	Verb	Adverb
airsickness	Yes	No	No	No
air sickness	Yes	No	No	No

As nouns, airsickness and air sickness are synonyms defined as:

airsickness and air sickness: motion sickness experienced while traveling by air (especially during turbulence)

airsickness (noun)	air sickness (noun)
motion sickness experienced while traveling by air (especially during turbulence)	motion sickness experienced while traveling by air (especially during turbulence)