In recent times, airlines have seen a significant rise in the number of emotional support animals boarding flights. Data from airline companies suggest an estimated 100,000 animals travel in cabins in the US every year.

These animals are said to help many people deal with stress and help lower their blood pressure while flying. However, dangers they pose to other travellers and flight operations have led to imposition of certain restrictions on which types of animals can fly.

Recently, an "emotional-support peacock" was denied access to travel with its owner on the United Airlines flight at Newark Liberty International Airport, New Jersey because it did not meet certain guidelines for a number of reasons, including its weight and size.

Even after the airlines explained the issue to the customer on three separate occasions, she brought the large bird to the airport and insisted on taking it along on the flight, travel blog Live and Let Fly reported.

The airline operator said they were reviewing their policies regarding allowing service animals on flights to accommodate more requests from passengers.

Not just United Airlines, but other operators too are now reviewing their policies about the right to let these animals' board flights.

Rise in service animals travelling by flights

According to Delta airlines, it carries approximately 700 service or support animals daily — nearly 250,000 annually. The airlines announced on 19 January that they are tightening rules on who can take emotional support animals on flights, following an increase in the number of people bringing animals on board. The new rules will come into effect on 1 March.

"The rise in serious incidents involving animals in flight leads us to believe that the lack of regulation in both health and training screening for these animals is creating unsafe conditions across US air travel," John Laughter, Delta's senior vice president of corporate safety, security and compliance, reportedly said in a statement.

The airline company added that since 2016, they have witnessed an 84% increase in reported animal incidents on board flights, which includes urination/defecation and biting.

In June 2017, a man was attacked by a 70-pound emotional support dog on board a flight a Delta flight from Atlanta to San Diego. Marlin Jackson said he required 28 stitches after the huge Labrador thrashed him on his face while he sat on his window seat, next to a man who had the dog sitting on his lap, according to Washington Post.

Guidelines for carrying service animals

According to the Department of Transportation's guidelines for air travel with service animals, "unusual animals are evaluated on a case by case basis". However, the guidelines clearly states that too large or heavy and violent animals cannot be carried as service animals.

Airlines too have some liberty to deny access to certain "unusual" service animals, which include snakes, other reptiles, ferrets, rodents and spiders. Even when deciding to allow animals such as miniature horses, pigs and monkeys, the airlines must first see if these animals are not a threat to others, the guidelines further state.

Also, federal laws require passengers traveling with animals for emotional support to provide recent documentation from a mental-health professional for their pets, however, these documents are sometimes forged to get the animals in, Washington Post reported earlier this month.