I've had a couple of carsick puppies. Both grew out of it when they were about a year old. (I also had a carsick senior Greyhound. She never did get better.)
I've tried _everything_ for car sickness, from ginger to anti-static straps on the car. The only thing that worked with some reliability was Gravol, the original formula, not the ginger version. It can make a dog sleepy, although it didn't bother Daisy. You'll need to check the dosage with a vet.