Did you know if a dog or cat can't stand-up and turn-around, their travel crate is too small.
During shipping, the animals are to be confined in containers that must allow for normal habits and freedom of movement. The animal must be able to sit and stand up in a natural position with its head erect, have enough space to turn about normally while standing, and to lie in a natural position.
This might sound like it's just for comfort, however this is a requirement for travel under USDA's Animal Welfare Act Regulations. Airlines can and will deny the transport of your dog or cat if the travel crate is too small.