United Airlines said this week that starting June 18 it would no longer transport dozens of breeds with short or snub noses, including bulldogs, boxers and pugs, in the cargo hold, because studies have shown that they have difficulty breathing in planes.
Passengers can still bring small pets, including many of the breeds banned in cargo, into the cabin if the animal's carrier fits under the seat without obstructing passengers from exiting.
But the policy, which doesn't address service and emotional-support animals, also bans the transport of animals in crates bigger than 30 inches tall anywhere on planes.
The petition on Change.org says United has been the most affordable airline for transported animals, especially large breed dogs such as Labradors, golden retrievers and huskies — breeds that can only be transported in crates more than 30 inches tall.
"I have a German Shepherd and we are living in the UK as a military family," Ashley Swearingin wrote on the petition site. "I can't imagine how we will get our baby girl home now."
Another military family member, Lynette Layne, wrote on the petition site: "SEMPER FI, Always Faithful!!!! We should as a country never leave a man, woman or animal behind!!!"
The new policy may cause some hardship with military families based in Guam, where United Airlines is the only major U.S.-based carrier serving routes to the mainland.
The carrier said Thursday that it will allow military families and State Department and foreign affairs personnel to book new reservations to transport their pets out of Guam under the previous regulations — but only until the new policy takes effect June 18.
"Unfortunately, we are unable to provide any other exceptions," said United spokesman Charles Hobart. "We know this can present challenges, but we hope our customers understand that we are making these improvements to help safeguard the health and safety of pets in our care."
In most cases, travelers could book flights on other major U.S. airlines, some of which allow large breeds but tend to charge higher fares.
The changes were prompted by the death of a 10-month-old French bulldog on a United Airlines flight in March from Houston to New York — a story that went viral on social media. United also flew two other dogs to the wrong destination in the days after the bulldog scandal.
After the incident, United stopped transporting all animals in the cargo compartment, the service that it will relaunch starting June 18.