I know an Air Force pilot who was struggling with airsickness in primary training. A few sessions in the torture device below cured it, and they are now flying F-16s.
https://www.cnet.com/news/the-chair-that-stops-you-from-vomiting-in-flight/
https://www.cnet.com/news/the-chair-that-stops-you-from-vomiting-in-flight/