Washington (CNN) A federal proposal unveiled Wednesday would significantly limit the types of animals entitled to fly in aircraft cabins as emotional support animals.

It's a crackdown the industry has sought amid concerns some passengers are bringing their untrained pets aboard by fraudulently passing them as emotional support animals. The result, the industry and Transportation Department have said, is an increase in incidents such as bitings aboard planes.

"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-CWA, which represents 50,000 crew members.

The proposal would free airlines from the requirement to accommodate passengers' emotional support animals and reclassify them as pets. Airlines have greater leeway to determine their pet policies, including charging passengers fees and setting size limits.

It would continue to require airlines accommodate service animals, but restrict that category to dogs only. The current regulations allow a limited list of service animals species, including miniature horses.

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