J.B.
My 4 year old has had this issue for a few years -and I did/do too. We basically make sure he has a plastic bag he can reach in case he needs to vomit and he has an air vent above his head, so we blow cool air on him. I know it does help for me to be quiet and put my head back with my eyes closed. He also cracks his window frequently to let fresh air blow on him. We do use Dramamine for any trip over an hour.