The federal government wants to put a stop to the petting zoo in the sky.

Regulators at the U.S. Department of Transportation proposed a new rule Wednesday that would allow airlines to ban untrained emotional-support animals from airplane cabins, reserving that privilege for fully trained service dogs that help people with psychological or physical disabilities.

The same day, Delta Air Lines announced it now offers a deluxe animal crate that can be tracked like luggage, an option the airline’s executives hope will lead more passengers to put their pets in the cargo hold rather than carry them aboard.

Delta’s kennel, developed and produced by Singapore-based CarePod, is also designed to reduce injuries and deaths to pets transported as cargo.

The DOT’s action follows years of debate over whether an emotional-support animal should be given the same travel access as a fully trained service animal. Under the proposed rule, only dogs with special training would qualify as approved service animals. Peacocks, goats and other animals would have to travel below.

The proposed rule has a 60-day comment period and could go into effect any time after.

Airline executives have argued the rising number of untrained — and sometimes ill-behaved — comfort animals has caused problems for people with physical and psychiatric conditions who rely on trained service animals.

Veterans and disability groups, whose memberships include people who rely on trained service animals, also say the swelling number of comfort animals is creating a public backlash against all animals on planes. They support better definitions and restrictions for animals approved to fly with their humans.

“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, chief executive of Airlines for America, the leading lobbying association for the U.S. airline industry, of which Delta is a member.

The proposed rule defines service animals as “a dog that is individually trained to do work or perform tasks for the benefit of a qualified individual with a disability, including a physical, sensory, psychiatric, intellectual, or other mental disability.” However, the rule also prohibits airlines from banning specific dog breeds, though airline employees can refuse to board any animal they consider a threat to other people. Delta currently bans pit bulls.

Some travelers have sought certifications for emotional-support animals to avoid paying the pet fees. Others have done it because they’re afraid a pet will die or be injured in cargo. In 2018, 10 pets died while being transported on U.S. airlines, including four on Delta, according to DOT’s most recent full-year data.

In some instances, animals in flight chewed through kennel walls, resulting in injuries or deaths from a variety of causes.

CarePod says it spent five years refining the design of its kennel and another two months testing it in Delta’s launch markets. CarePods will now be available for $800 plus taxes on Delta flights that begin and end at eight different airports, including Minneapolis-St. Paul International Airport, the airline’s second-largest hub.

The companies herald the pink-and-white crates as “state-of-the-art.” They feature built-in water bowls that automatically refill and thick walls animals can’t chew through.

“It’s got ventilation holes in it, but there is no way for an animal to bite through it,” said Debbie Egerton, a Delta spokeswoman.

Pet owners can view their animal’s location through updates on their smartphones, while Delta’s cargo center digitally tracks the pet’s journey.

In 2018, Delta transported more than 75,600 animals as cargo, second only to Alaska Airlines among U.S. carriers.

While the DOT’s proposed rule goes through its feedback period, Delta’s service and support-animal policies have not changed. The airline said it is working with the agency to “support the rights of customers who have legitimate needs to travel with trained animals.”

CarePods are available for flights between the eight launch airports — Atlanta, Boston, Los Angeles, Minneapolis-St. Paul, New York (both JFK and LaGuardia airports), San Francisco and West Palm Beach — by reservation three to 13 days before the flight. In the next few months, Delta will expand the service to four more airports: Detroit, Seattle, Salt Lake City and Kansas City, with an eventual rollout nationwide.