Miniature horses are still officially allowed to travel on planes as service animals, according to new guidelines from US officials.
The US Department of Transportation issued a "final statement of enforcement priorities" to clarify that miniature horses would still be allowed onboard commercial planes, as well as cats and dogs.
There has been ongoing recent conversation around which support animals are allowed onboard US flights following a number of controversies.
"With respect to animal species, we indicated that we would focus our enforcement efforts on ensuring that the most commonly used service animals (dogs, cats, and miniature horses) are accepted for transport as service animals," said the guidelines.
However, it is still up to individual airlines to rule on which animals are permitted onboard as comfort pets – as well as how many are permitted to travel with the passenger.
Various airlines have already ruled on which animals are allowed onboard.
American Airlines now only permits a cat, dog or miniature horse to be brought onboard as an emotional support animal.
Denver-based Frontier Airlines also only permits cats and dogs, which is the same policy as low-cost giant Southwest.
In the past, passengers have tried to board flights with animals such as squirrels, peacocks and a turkey.
The guidelines follow the case of a female passenger who is suing American Airlines after claiming cabin crew locked her emotional support dog in the plane bathroom during a flight.
Avigail Diveroli, from Florida, was flying in business class from Miami to Los Angeles with comfort dog Simba in April this year.
According to the lawsuit filed with the court in Miami, Ms Diveroli claims she was told to lock up Simba in the bathroom for the last part of the flight, adding that the cabin crew member “started slamming” the dog’s portable kennel with the door to the bathroom at one point.
Last month, a flight attendant required five stitches when he was bitten by an emotional support dog mid-flight.
