A woman passenger was booted from a US Airways flight after the pig she brought on board for "emotional support" became disruptive, the airline has said.
The passenger and her large pig were asked to leave the flight before it left Connecticut's Bradley International Airport on Wednesday, spokeswoman Laura Masvidal said.
"After the animal became disruptive, the passenger was asked to deplane," she was quoted as saying by CNN.
Fellow passengers told the Hartford Courant that the big brown pig stank up the cabin of the tiny Washington DC-bound aircraft before defecating in the aisle.
When passenger Robert Phelps first saw the woman coming down the aisle, he thought she had a "really big dog" or a stuffed animal thrown over her shoulder.
"Everybody was trying to surmise what it could be because no one thought it was a pig," he said.
After she reached her seat and began to stow her items, the pig began "dropping things" in the aisle, he said. As she tied him to the armrest and tried to clean up after him, he began to howl.
"She was talking to it like a person, saying it was being a jerk," he said. "I have no problems with babies, but this pig was letting out a howl."
A flight attendant asked her to move to the front of the plane, and eventually she left, he said. He took a photo of her as she walked past him.
"I understand dogs and cats on planes. They come in crates but this was way too big, and it had no container," he said. "It looked heavy. It was not a tiny, cute little pig."
The passenger was allowed to bring the pig on board as an "emotional support animal" under Department of Transportation (DOT) guidelines.
"We follow all DOT guidelines," Masvidal said.
"Emotional support animals" have become increasingly popular in recent years, thanks in part to those guidelines.
In 2003, the DOT updated its policy regarding animals in air transportation to say "animals that assist persons with disabilities by providing emotional support" qualify as service animals.
It's up to airline personnel to determine whether an animal is a service animal.
When it comes to emotional support animals, airlines may require supporting documentation from a mental health professional.
It is not clear whether the passenger on Wednesday's flight provided such documentation, the report said.
