United Airlines on Friday joined a growing list of carriers that are banning emotional support animals on flights, the company said.

United joins American, Delta, Alaska and JetBlue airlines in no longer allowing any animal on board in the cabin for free unless it is a service dog.

Starting Monday, the Chicago-based carrier will no longer let passengers book travel for companion animals, according to USA Today . For people who book before the deadline, free travel for companions will end on February 28.

Other animals will be able to fly on United but only in the cargo hold, or only in a carrier that fits under a seat in the cabin. No more trips in a seat in the cabin, and there will be a pet fee of $125 per flight.

The airlines are reacting to a U.S. Department of Transportation’s ruling last month that no longer requires carriers to make the same accommodations for emotional support animals as they do for trained service dogs.

Changes to the DOT rules came after feedback from the airline industry and disability community regarding numerous instances of emotional support animal misbehavior which caused injuries, health hazards and damage to aircraft cabins. The types of animals passengers were bringing onboard included ducks, ferrets, pigs, even miniature horses.