The Department of Transportation’s (DOT) draft manual on equity for the disabled in air travel now states that "unusual animals such as miniature horses, pigs and monkeys" may accompany passengers in the cabin of an airplane if they are considered "service animals" or if they provide necessary "emotional support."
Foreign country restrictions, the size and weight of the animal, and passenger concerns all need to be taken into account, but apparently a 300 pound pot-bellied pig was allowed to fly on a US Airways flight last November, so there seems to be room for interpretation.
The manual's example for airport employees reads:
A passenger arrives at the gate accompanied by a pot-bellied pig. She claims that the pot-bellied pig is her service animal. What should you do?
Generally, you must permit a passenger with a disability to be accompanied by a service animal. However if you have a reasonable basis for questioning whether the animal is a service animal, you may ask for some verification. Usually written verification is not required.
Finally, if you determine that the pot-bellied pig is a service animal, you must permit the service animal to accompany the passenger to her seat provided the animal does not obstruct the aisle or present any safety issues and the animal is behaving appropriately in a public setting. [Emphasis added]
But CNS News has more information:
According to the DOT guidebook, if an animal is not accepted, the carrier must document the decision in writing and provide it to the passenger within 10 days.
Carriers must also provide “relief areas” for service animals. “With respect to terminal facilities you own, lease, or control at a U.S. airport, you must, in cooperation with the airport operator, provide relief areas for service animals that accompany passengers with a disability who are departing, arriving, or connecting at an airport on your flights,” the manual states.
Watch Fox News' "Red Eye" panel sarcastically discuss the changes (and how it could deter terrorism), below:(H/T: CNS News)