If you travel by car, either a hard plastic or wire crate will do. Some wire crates fold down for storage and portability, which comes in extremely handy if your situation requires that you move the crate in and out of your vehicle. What size should the dog crate be? Well, take a good look at your dog! The crate should be large enough so that the dog can stand up, turn around, and lie down comfortably, but not so large that the dog slips around during travel.