Redundant Array of Inexpensive Kittens
Target had some small plush animals on sale for a buck each. We grabbed three kittens for our daughter, who loves cats. This formed the basis of our Redundant Array of Inexpensive Kittens (RAIK -- compare with RAID).
The kittens stay in the car. One hangs in the back seat with her; the other two up front. She can play happily with the one she has in the back. If she should drop one and we can't reach it while driving, we can fail over to one of the ones up front.
This has worked so well there is another array in my wife's car.
As an added bonus, they fit easily into a pocket, to take into a restaurant or waiting room, and serve as good entertainment. With a low initial investment, it is not too heartbreaking if one should get lost or damaged.