United Airlines can't catch a break, as a giant bunny set to be the world's largest just died on one of the airline's planes and it's a mystery how it happened.

Hot on the heels of the recent United Airlines scandal regarding forcibly removed passengers, the airline is now in trouble again as a huge bunny died while being transported to its new "celebrity" owner.

Giant Bunny Dies On United Airlines Flight

A giant bunny named Simon, measuring 35.4 inches in length, died in the cargo hold of a United Airlines plane while traveling from London Heathrow to Chicago's O'Hare airport. The crew found him dead when the flight arrived at its destination.

According to reports, the 10-month-old bunny was on its way to its new "celebrity" owner. Simon was expected to become a record breaker for bunny size, outgrowing his father which holds the current Guinness World Record for the world's largest rabbit.

Simon was a Continental Giant specifically bred for his gigantic size. Breeder Annette Edwards was shipping the bunny to its new owner in the United States and can't grasp what happened, since the bunny had a full checkup before boarding the plane and was in excellent condition.

"Simon had a vet's check-up three hours before the flight and was fit as a fiddle," Edwards told the Sun. "Something very strange has happened and I want to know what. I've sent rabbits all around the world and nothing like this has happened before. The client who bought Simon is very famous. He's upset."

United Airlines Investigating Giant Bunny Death

United Airlines, which already swims in troubled waters and continues to face bad publicity, says it's "saddened" by Simon's untimely demise.

Unfortunately, it's not such a rare occurrence. According to data [PDF] from the U.S. Department of Transportation, U.S. airlines have reported 35 animal deaths in 2015. No data is available for more recent years, but more animals have died on planes since then.

Of those deaths recorded for 2015, 14 were on United Airlines flights, which also accounted for nine animals injured. The airline transported 97,156 animals in total that year, which translates to a rate of 2.37 incidents for every 10,000 animals carried. According to the stats, that was the highest rate for any airline in the United States.

United Airlines is now investigating the circumstances leading up to Simon's death.

"We were saddened to hear this news. The safety and well-being of all the animals that travel with us is of the utmost importance to United Airlines and our PetSafe team," the airline told the BBC. "We have been in contact with our customer and have offered assistance. We are reviewing this matter."

However, Edwards told NBC News that the airline has not been in contact with her. United Airlines now faces legal claims from both Edwards and Simon's new owner, who never got his giant bunny.

United offered no further comment at this point, but is expected to release more details once it completes its investigation. For now, it remains unclear just when the rabbit died or why. As always, we'll keep you up to date as soon as we learn more.