Try Benadryl? Makes them sleepy, lessen the stress. I don't know where puppy rides but a different spot maybe.
Vet told me to give it to the cat when we moved, of course she refused to take it, but dogs are different, they eat anything.
He rides in the backseat usually. I’m scared to test him in the front because that is even bigger nightmare to have to clean up. Hopefully we don’t have to find out!