Thanks. When I take trains (mostly in Europe), I always sit facing forward out of a worry that I may get motion sickness if traveling backwards. However, this may be more psychological than physiological, because on occasions when I had to face backwards, I didn't get motion sickness during the ride.

I've never flown backwards though, but it should be better because plane rides are generally more smooth than train rides except during episodes of air turbulence. I hadn't thought about the taxiing part, but perhaps that is about the same as a typical train ride in terms of motion?