airsickness vs motion sickness

airsickness and motion sickness both are nouns.

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

As nouns, motion sickness is a hypernym of airsickness; that is, motion sickness is a word with a broader meaning than airsickness:

airsickness: motion sickness experienced while traveling by air (especially during turbulence)
motion sickness: the state of being dizzy or nauseated because of the motions that occur while traveling in or on a moving vehicle

Other hypernyms of airsickness include kinetosis.

airsickness (noun)	motion sickness (noun)
motion sickness experienced while traveling by air (especially during turbulence)	the state of being dizzy or nauseated because of the motions that occur while traveling in or on a moving vehicle