There's a simple solution to maintaining your pleats while getting into a car. Simply keep a large towel in the car to use for this purpose.

Before you slide in, wrap the towel around your kilt... making sure that the pleats are hanging straight first. Center your "backside" in the towel, then pull the sides to the front. By wrapping it tightly as you get in, the pleats maintain their form and you don't MANGLE them while driving. When you sit down, just release the sides of the towel and sit on it while you drive. No need to pull it out and take the chance of messing-up what you've just tried to prevent!

This is the ONLY solution that I've had for my thinner material kilts. The thicker, wool ones can benefit from the treatment too.