As more people bring “emotional support animals” on board planes — including pigs, turkeys, monkeys and other unusual pets — airlines and mental health advocates are debating whether the practice should continue.

Both sides are meeting this week in the Washington, D.C. area to come up with recommendations for a Department of Transportation panel, with the sixth and final meeting scheduled next month.

Animals can soothe fliers suffering from anxiety, panic attacks and phobias. But air carriers are frustrated that many healthy passengers are abusing the rules, claiming their pets are therapy animals to fly them for free in the cabin.

'An airborne Noah's Ark'

It's also an issue for passengers with allergies and crews who must deal with the critters. Some flight attendants complain cabins now look like barnyards.

Easter, a Wild Turkey, is a registered "emotional support animal" so she's allowed on planes https://t.co/PJCOh2ikDm pic.twitter.com/tTRcn5osaT — Nicolas Gonzalez (@NicoSGonzalez) March 24, 2016

“The ‘emotional support animal’ situation is out of control,” Henry Harteveldt, travel industry analyst at the Atmosphere Research Group, told TODAY. “Most passengers don’t want to be on an airborne Noah’s Ark.”

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As TODAY national investigative correspondent Jeff Rossen found out, it’s easy to get a pet designated an emotional support animal. All you need is a special vest and an official letter from a mental health professional. Lots of websites offer certifications; all you have to do is fill out a questionnaire.

Related: Emotional support animals are making flying beastly, experts say

“There is no question that some people cheat,” said George Hobica, founder of Airfarewatchdog.com. “Figuring out who the cheaters are is the hard part and may defy solution.”

Major U.S. carriers are in favor of no longer recognizing emotional support animals at all, or at least limiting the species allowed on board, according to a letter written this summer by a working group that's co-chaired by an American Airlines attorney and includes United, JetBlue, Delta and Frontier.

The letter called therapy pets “by far the source of most of the fraud and other problems” created by the current rules.

No special training

Mental health advocates also say it’s a difficult issue.

For Alicia Smith, who co-chairs the same working group on behalf of the National Alliance on Mental Illness, the main goal is to change the rules so that psychiatric service dogs — trained to help people with mental illness maintain balance or take medications, for example — are in the same category as service dogs helping people with physical disabilities. She believes there will be few objections to make that happen.

But emotional support animals, which don’t get special training and help their owners simply by being there, should still be recognized by airlines and not limited to a certain size or species, Smith believes.

“If they limit it to dogs, that becomes problematic. Dogs can be fairly high-maintenance, but a child who has autism [may be] calmed down by stroking a bunny’s fur,” she said.

“If they [limit the size], a lot of people who have existing emotional support animals will not be able to travel with them. What you’re saying is, these people can’t go home for Christmas if they have to fly.”

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This is things that have gone to far: A rooster on a plane, in a pink tutu, as an "emotional support" animal. pic.twitter.com/PLpuf4EH5Z — Sue Strachan (@SueStrachan504) September 15, 2014

Both sides have been meeting since April to consider differences between the Air Carrier Access Act, which requires airlines to fly all service animals, except “certain unusual animals” such as snakes, ferrets, and spiders; and the Americans With Disabilities Act, which only recognizes dogs and miniature horses as service animals.

“Travelers' abuse of emotional support animals makes it necessary for airlines and mental health advocates to collaborate to find reasonable, pragmatic, and enforceable compromises,” Harteveldt said.

“If reasonable compromises can’t be agreed upon, however, I believe airlines will argue that only service animals should be allowed on a plane.”

That would align the United States with the rest of the world. Emotional support animals are not accepted by airlines in other countries, according to the International Air Transport Association.

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