WASHINGTON • It has been a frightening week for dog owners considering putting their pets on airplanes.

First, there was a report on Tuesday that a puppy died on a United Airlines flight after a flight attendant demanded that the dog's owner stow it inside the overhead compartment for the three-hour journey.

Now, this: A Kansas-bound german shepherd may have mistakenly been shipped to Japan by United Airlines.

In the first incident, the attendant insisted that the bulldog's owner, Ms Catalina Robledo, put her pet, which was in a dog carrier case, in an overhead storage locker during a 31/2 hour flight from Houston to New York on Monday.

Her 11-year-old daughter, Sophia Ceballos, in an interview with CBS, recounted her reaction when the attendant ordered that the dog carrier case be placed in the overhead bin.

She told CBS: "I was like 'It's a dog, it's a dog. He can't breathe there.' (The flight attendant) was like 'it doesn't matter'."

The family told CBS they heard the puppy barking for two hours during the flight before going silent. The family said they were unable to check on the dog because of turbulence that forced them to stay seated.

The United States Department of Transportation "is looking into the circumstances surrounding the recent death of a pet on board a United Airlines flight", an agency spokesman said on Wednesday.

The US$125 (S$163) fee that Ms Robledo paid for her dog to fly in the cabin and the cost of the airfare have been refunded.

In the second incident, a family moving from Oregon to Wichita paid to have their dog, Irgo, shipped as cargo on a United flight, according to KCTV in Kansas City, Missouri,

But when the family went to United's cargo centre at the Kansas City airport, they were met by a great dane that was inside a pet carrier that looked similar to Irgo's.

The great dane was supposed to have been en route to Japan, said United staff, and Irgo could possibly be on the plane to Japan instead.

According to United Airlines, Irgo has been located and is on the way back to its family.

Several high-profile incidents of animal deaths and misplacements on United flights have plagued the airline over the last year, including the death of a giant rabbit on one of its flights last July and a dog that died in a plane cargo hold in August.

WASHINGTON POST, REUTERS