Sydney uses the
Travelin' Dog Pet Seat . I bought it from PetSmart, but I don't think they have it anymore. As it was, when I ordered it, it was on backorder. It works great, though. The seat also received good ratings. Syd, unfortunately, whines and barks while traveling in the car. If we're going down the road for a while, she'll eventually calm down and lay in the seat. But as soon as a turn signal comes on, she's whining and barking.
Amazon.com: Good Pet Stuff Travelin' Dog Pet...