By Amy E. Feldman

PHILADELPHIA (CBS) – Emotional support sounds like something your girlfriend talks about. Guess what? So does the law.

A passenger and the large pig she said was an emotional support animal were booted off a US Airways flight over Thanksgiving after the pig ran up and down the aisles and then soiled the carpet. Sounds like trying to bring a toddler on a plane. But if the woman really relied on the pig as a support animal (because you know, with support like that, who wouldn’t want one), doesn’t the law give service animals special rights?

The Americans With Disabilities Act gives people the right to bring service animals in places where they are not otherwise allowed, but the definition of a service animal are animals that are trained to perform tasks that their handlers cannot do for themselves.

A business that wants to determine if the animal is a service animal can only ask two questions: Is the animal required because of a disability? And what task has the animal been trained to do?

Dogs are covered under law and must be allowed into businesses, as are some specially trained miniature horses. But, the Department of Justice has said that animals that provide comfort or companionship for their owners but that are not trained to perform any specific tasks are not considered service animals under federal law.

For those animals whose presence, but not tasks, provide comfort, the law is still evolving. And for now, it turns out that pigs really can’t fly.