Try leaving the window open a bit (only an inch or two) so that the fresh air can get in. Like Rosie says once he can look out of the window he should be ok.
Kipper was travel sick when he was a pup. We built up the journeys slowly and took lots of breaks, but I think age has something to do with it, in that they’re more sensitive when they’re younger. Advice is often get them forward facing in the central line of the car (I guess minimizes rocking?) and give them fresh air but this didn’t seem to make a huge difference with Kipper.
I wonder if treats with ginger in might help?
We had the same with Barley when she was young and did much the same as Her Majesty, Queen of Turnips. Eventually Barley was fine, loved the car and quite often was reluctant to get out, particularly after camping trips!
It does seem to be young pups. Amber was like this until she was grown a bit too. She's fine now though. I think something with ginger in is a very good idea!
When I did a puppy course, the behaviourist recommended putting them in the foot well - idea being that it was better to be low to the ground, less movement.