The simple truth is that motion sickness has a number of variables: flight time, type of flight, turbulence, personal physiology, training. Everyone will get air sick under the wrong circumstances. We had 5,000 hour mission commanders get sick after eight hours of low-level bouncing around in a P-3 with the A/C out because of ADC failure (in the A- and B-models, the crew sat sideways, so turbulence was especially punishing).
Most people can get some immunity through experience and training.
Most people can get some immunity through experience and training.