ARLINGTON, Va. -- A 10-year-old German shepherd Irgo was supposed to be on a flight from Oregon to Kansas City, but when owner Kara Swindle arrived in Missouri, United Airlines gave her a Great Dane instead. The dogs got switched, and Irgo was sent to Japan.

"At this point all I can do is be hopeful that my dog is going to be OK," said owner Kara Swindle. "I've cried too much."

Kara Swindle / KCTV-TV

United says the error happened during the dogs' connection in Denver. On Wednesday, the airline apologized -- something it's done a lot of this week.

On a Monday night flight from Houston to New York, a flight attendant ordered Catalina Robledo and her 11-year-old daughter Sophia to put a bag in the overhead bin. Inside was their 10-month-old French bulldog, Kokito.

"She got the dog off and he was literally not moving," said Sophia.

Kokito died, and now United admits the family told the flight attendant about the dog, but she "did not hear or understand her, and did not knowingly place the dog in the overhead bin."

A puppy died after it was put in an overhead bin CBS News

More than a half million animals flew in 2017, nearly 140,000 of them on United. Overall, 24 died -- 18 of those also on United flights.

"What happened to this pet was disgraceful," said Louisiana Sen. John Kennedy.

The lawmaker has two dogs himself, and sent a letter to United demanding answers.

"We need to get to the bottom of it," Kennedy said. "I know we have many important things to do but this is important too."

United says Irgo will be home Thursday, and he'll be flying in the cabin with a human escort. The airline also says that starting in April it will issue brightly colored bag tags to customers traveling with in-cabin pets.