I am terrible when it comes to motion sickness - any flight over about 6 hours (one of the downsides of living in the antipodes) is absolute hell as is even the most moderately winding drive as a passenger. But when I am driving I have no problems - this dichotomy seems quite common, but I am not sure about the why. Perhaps it has to do with intent or a melding with the vehicle's etheric body when one is driving.