[mickey]

When our kids were smaller, we used to gate check our child seats. I am not sure if you are still able to do that, with the changes in security.

One option would be to call the rental car company. Many of the minivans now have built in child seats. We had a Ford and a Chrysler that did, so it is a possiblity. While they aren't the best child seats around, they work well and are very efficient.