The Department of Transportation is considering overhauling current rules for service animals on planes, including allowing airlines to prohibit those used for emotional support.

The proposed changes announced on Wednesday include only allowing specially trained service dogs to qualify as service animals, which ride for free in a planes cabin. Any other animal used for emotional support or simply to make a passenger feel better would be considered a pet and airlines would not be required to allow them on board, the DOT said.

The DOT would also prohibit airlines from refusing a service animal solely on the basis of breed. Delta Airlines has a controversial policy of prohibiting pit bull type dogs on its flights.

Passengers wanting to ride with Fido would instead have to fill out a federal form attesting that their dog is trained to do work or perform tasks for the benefit of a person with a disability. The dog would need similar proof of good behavior, good health and having the ability to not relieve itself or do so in a sanitary manner.