We are down to 1 dog. We used to travel with 3 Alaskan Malamutes.
For people with med to large dogs check out these. They are very sturdy and portable. Advantek™ Pet Gazebo, 5 ft. x 5 ft. x 5 ft.
104872499 $149.99 (price and info from Tractor Supply)
We use 2 of these to make a larger enclosure for one dog. You can connect quite a few of these together. All you do is turn the connector (top and bottom) to "out" from "in".