Southwest Airlines is putting restrictions on what emotional support animals you can take on board.
Starting next month only a cat or dog will be allowed on a plane.
Passengers will need to present a letter from a doctor and the animal must be on a leash or in a carrier.
Similar rules go into effect for trained service animals. Only dogs, cats and miniature horses will be allowed to fly.
Since the beginning of the year, American, JetBlue, Delta and United have all introduced similar policies.
It comes as fliers become increasingly bold with trying to bring different types of animals onboard.