Read here on yt, ginger snap cookies, it curbs nausea.
googled & found this:
Ginger can ease dog's motion sickness - Roanoke.com
Q: I have a 9-month-old Labrador that is constantly carsick. I have tried all the usual remedies like taking her on short trips, etc. I have also tried some motion sickness tablets, but they made her very dopey for the whole day and when I am only going to Roanoke it is hardly worth it. Have you any suggestions?
I have used ginger with good effect in both dogs and humans. The root of the ginger plant is a tasty way to prevent motion sickness. Most dogs appear to like ginger, so you should have no trouble getting your dog to eat it. Ginger cookies are probably the most palatable form as far as your Labrador is concerned. Ginger also comes in a crystalline form and in capsules; however, chopping up a small piece of the root may not be as appetizing.