Never had any problems with Alfie, but Rosie was car sick from day one. Short and longer journeys. I followed somebody elses advice on here and put her as high up as I could [ they ride on the back seat on proper safty seat belt attatchments], by putting a large dog tick dog cushion bed on the seat. I also got the DAP pheramone in a spray and put some on the bed. They've been out the last 2 Sundays and no sickness.
Though she is now almost 9 months and may have simply grown out of it. She lies very quietly in the car, just aswell as Alfie is a whinger.