Loki stays in his car seat. I got it at Petsmart for $20 and it's in the back seat. I think it is meant for the front seat, but our SUV has headrests on the split bench in the back and it works fine there.
http://www.kyjen.com/pettravelgear/p...luxepetlookout
He loves it because he can see out or curl up and sleep. He just likes to be in the car with us and not stuck home alone.
I admit I have taken him out on long trips (2+ hours) - I sit next to him and let him sit on the back seat next to me.