For context, United transports more animals in the US than any other airline: Last year, the airline transported about 27 per cent of all animals flown as air cargo. 

Even so, people saw these disproportionately high numbers from 2017 as evidence that United has a history of mistreating animals, and that the airline is inherently less safe for transporting animals than any other major US carrier.

And United’s steep numbers aren’t new.

Going back further, United also reported the highest numbers of animal deaths in 2015 and 2016, especially when compared with other major US carriers like Delta and American. 

(Spirit, Southwest, JetBlue and Virgin America do not transport animals on their planes.)

But it turns out that United’s sky-high numbers of recent pet deaths may be more complicated than they initially appear.

While United does carry a disproportionate number of the animals who die on planes, the airline says the disparity results from one simple variable: United accepts higher-risk dog breeds that other major US carriers do not allow.

These types of dogs are known as brachycephalic, or “short-nosed” or “snub-nosed”, breeds. Their airways are more compact, which tends to lead to respiratory issues.

The short-nosed breeds include bulldogs, boxers, pugs, Boston Terriers, Pekinese, mastiffs, Shih tzus and others.

For years, carriers like American and Delta have refused to ship these types of dogs, arguing that the risk of death or injury (and liability to the airline) was too high.

Up until last month, United continued to accept snub-nosed breeds for cargo shipments.

The airline’s rationale: For people who needed to travel with a boxer or a bulldog, United was often the only way their dog could travel by air.

United says they consistently alerted customers to the heightened danger of putting their higher-risk dog on a plane. But ultimately, they say, airline representatives left it to customers to decide if their pet could handle the trip.

That explanation for the disparity is borne out, at least somewhat, by data on animal deaths kept by the US Department of Transportation.

A review of the recorded animal deaths from 2015 to 2017 indicates that in those three years, 85 animals died while in the care of a US air carrier. Of those deaths, 41 occurred on United.

Nearly 40 per cent of those deaths occurred to a dog that was identified as a higher-risk breed – a breed that is barred on American or Delta airlines.

In many of those cases, postmortem examination of the animal led the airline to conclude that there was nothing they could have done to prevent the animal’s death.

The deaths of these higher-risk dogs made up half of all dog deaths; there were also a handful of cats, reptiles and birds that died while in United’s care during those three years.

Of the three largest airlines that accommodate animals – United, Delta and American – the type of dog that died most frequently from 2015 to 2017 was the American Bully, a breed known for its big jowls and squashed nose.

Five of the six of those American Bully deaths occurred on United, because the dog is banned by Delta and American Airlines.

(Delta made an apparent exception for one such dog in 2015; that dog died en route from Savannah, Georgia, to Atlanta, the first leg of a longer flight.)

Of the nine dog breeds with the highest incidence of death on these three major airlines, four are brachycephalic breeds that are only allowed on United.

So, why not ban those breeds from flying altogether?

That is something that United may consider. The airline has temporarily suspended its animal shipping programme, at least until May, as company officials conduct a top-to-bottom assessment of its own animal cargo practices.

They may decide that those animals are too high-risk, and that the financial opportunity cornering the market on transporting America’s population of pugs and bulldogs may not worth the legal liability.

Still, an all-out ban could be onerous for the owners.

Charles Hobart, a spokesman for United, noted that United accommodates 3,000 pet-owning military families annually. 

When those families own a brachycephalic dog, and they are reassigned to an overseas military posting, United is sometimes their only means to ship their pet. Otherwise, they would have to give their dog away.

“Our goal is to help keep families together, and dogs are part of the family,” Hobart said. “A lot of times, families just don’t have an option.”

Kitty Block, acting president and chief executive officer of The Humane Society of the United States, said that’s no excuse for the higher rate of death on United flights. 

She doesn’t want to see an all-out ban on the snub-nosed dogs, she said. Instead, she wants United to find ways to accommodate the special needs of those riskier breeds.

“The fact is that while there is some risk with travelling with a brachycephalic breed on a plane, travelling with them in the cabin can be done safely if the right measures are taken by both the owner and the airline,” Block said.

“And that is what we’re asking for – that airlines take steps to reduce the risk of flying with pets, regardless of breed, as much as possible.”

In the meantime, Hobart said, United is taking other steps to improve the quality of service for people transporting their pets by air – particularly in light of another high-profile incident, in which a German shepherd was accidentally sent to Japan instead of its intended destination of Kansas City, Missouri.

Hobart said the company has instituted new procedures to ensure that animals are loaded onto the correct airplane, and that animals are not accidentally left behind, or sent to the wrong destination.

From now on, Hobart said, “a member of management will be on the ramp to confirm that the loading and offloading is taking place in compliance with the planned route of flight and manifest.” 

The new procedures require another manager follow-up with the data provided by the ramp supervisor “to cross-check and verify before an animal can be released for departure,” he said.

Additionally, United will now automatically send daily reports to airport managers around the country, alerting them about what animals to expect to arrive and depart from their airport on the coming day.

“It sounds a little cumbersome, but it’s not,” Hobart said. “It’s going to minimise the risk of an animal travelling to a destination where it’s not supposed to go.”