My DS hated the car as a little baby. From newborn until about (and I apologise for this bit of news) 12 months, he screamed for the entire journey when we went anywhere in the car.
I don't know if he was car sick (he is still rear facing now at 23 months and doesn't seem to suffer) or what, but he hated it, and used to make himself sick screaming relatively regularly.
At around 12 months it started to improve - if we left at nap time, he would have a little snooze in the car (then start screaming), and for short journeys he wouldn't scream.
Even now he only tolerates it, rather than being happy, and is not a great coper if we get stuck in traffic, but he is a million times better than he used to be.
As DS began to improve, we could get 30-40 good minutes, so broke up long journeys (e.g. to my parents, 3 hours away) into several chunks, with long breaks at service stations etc in between. It meant travelling took bloody ages, but was less stressful. We also sometimes used to travel at night, rocking him to sleep in car seat before we left.
But mainly, we suffered until he improved 