The Australian laws stipulate that the animal has to be able to stand and turnaround without touching the container. They will not allow two to travel together, and you have to get a certificate signed by a vet that they are fit to make the journey within a day. There are a number of things to consider about flying, and when I shipped to USA they were put in the cargo and not let out for 16 hours during the flight - just as well. When I shipped to Hawaii, no rabies there, he held onto everything, and as soon as he was out of his crate at the other end, he had a gigantic piddle. And smiled.