Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
And for anyone, someone who:
Routine medical follow-up is reasonable if airsickness is frequent, is becoming worse, prevents necessary travel, or does not respond to basic measures.
A clinician or pharmacist can review prevention options and check for medicine interactions or conditions that affect treatment choice.
Arrange an evaluation if nausea, spinning, or imbalance continues beyond the expected period after travel; occurs when you are not moving; or appears with hearing loss, ear symptoms, migraine-like symptoms, or repeated falls.
These patterns are not typical enough to assume they are simply airsickness.
The article also says
Before a future flight, note what happened during the previous episode.
Useful details include the seat location, turbulence, food and alcohol intake, sleep, activities such as reading, medicines taken, and how long symptoms lasted.
This information can help identify practical changes.
People who are pregnant, traveling with children, older, or managing glaucoma, urinary problems, heart disease, or several medicines should seek advice before using a motion-sickness product.
Every sign above is quoted from the sofidex article on Airsickness. If you are not sure, err upward — it is always reasonable to be checked.