A new rule proposed by the U.S. Department of Transportation would allow airlines to stop accepting emotional-support animals on planes.

Only professionally trained service dogs would be welcomed.

The proposed rule comes after complaints from flight attendants and other passengers about behavior of such animals on board. It prompted the DOT to review the policy.

The agency says people tried to pass their animal as an emotional support animal to avoid paying the associated fees. Brad Hibbard, of the Guide Dog Foundation, says that kind of fraud “erodes the public’s confidence around legitimate service animals having public access."

The DOT is seeking public comment for the proposed policy. The public will have 60 days to submit its comments.