(AP) — The days of passengers bringing rabbits, turtles and birds on planes as emotional-support animals could be ending.

The U.S. Transportation Department on Wednesday announced plans to tighten rules around service animals, the biggest change being that only dogs could qualify.

Airlines say the number of support animals has been growing dramatically in recent years, and they have lobbied to tighten the rules. They also imposed their own restrictions in response to passengers who show up at the airport with pigs, pheasants, turkeys, snakes and other unusual pets.

“This is a wonderful step in the right direction for people like myself who are dependent on and reliant on legitimate service animals that perform a task to mitigate our disability,” said Albert Rizzi, founder of My Blind Spot, which advocates for accessibility for people of different ability levels.

The U.S. airline industry trade group praised the tighter rules. Industry officials believe that hundreds of thousands of passengers scam the system each year by claiming they need their pet for emotional support. Those people avoid airline pet fees, which are generally more than $100 each way.

“Airlines want all passengers and crew to have a safe and comfortable flying experience, and we are confident the proposed rule will go a long way in ensuring a safer and healthier experience for everyone,” said Nicholas Calio, president of Airlines for America.

Flight attendants had pushed to rein in support animals, too, and were pleased with Wednesday’s proposed changes.

“The days of Noah’s Ark in the air are hopefully coming to an end,” said Sara Nelson, president of the Association of Flight Attendants. The union chief said untrained pets had hurt some of her members.