Well, it's pretty easy to simply avoid rollercoasters!!
As for air sickness, Dramamine has always worked for me. However, it does make me very sleepy and out of it. I cannot drive after I have taken Dramamine. The effect of 1 children's strength lasts me about 6 hours (mainly, I sleep the entire time). But, it has saved me on multiple trans-Atlantic flights and I would never travel without it.
There's another product (I think it's called Bonine?), but that doesn't work for me.
That being said, I used SeaBands, years ago, when I was in my first trimester of pregnancy when dh & I had to fly to NY for fil's heart surgery. Since I couldn't use Dramamine, the doc suggested the SeaBands. I bought them at a chain drug store. We had pretty bumpy flights (it was December) on top of my morning sickness. I was still nauseous but I never did throw-up. I ate a LOT of crackers on those flights!
I can't use the patches as they make me even more nauseous and very woozy. I've had them as part of pre-surgery anesthesia (supposedly to keep me from throwing-up when I awake. Never worked and I threw-up, felt woozier than without the patch and waaaaaaaaaay more nauseous!! I always refuse the patches and tell the anesthesiologist "NO WAY"
That being said, I know people that love the patches. You have to get them from a doctor (they're by RX only).
Crystalized ginger is a wonderful anti-nausea treatment. No side effects, tastes good and really helps with the icky feelings. I always take it when we go out on the lake. I keep a can in the car for emergency use.