If ten ppl want to fly their dogs on the one aircraft, its not happening. If Great Dane is already booked on your flight, a budgie aint going.
What are the chances of ten people turning up for the same flight with their pets, including a Great Dane and a Budgie?
You're over-thinking it.
I was chatting to our Vet about pets and travel. He highly recommends a Sedative before travel.... for the pet owner!