Passenger furious because he has to give up his first-class seat - for a dog!

USA - A rollercoaster of emotions: A passenger has vented his anger after having to give up his first class seat to a dog!

"This morning I was upgraded to first class, only to be downgraded 15 minutes later (to a worse seat than before)," wrote user "ben_bob" on the social news aggregator reddit yesterday (local time).

He then asked an employee of his airline Delta Air Lines at the counter how this could have happened.

"Something has changed," he was told. Annoying, but it can happen, according to the passenger. Once on the plane, however, he was shocked: "Then I get on, only to see this dog in my first-class seat ... And now I'm furious."

The dog in his seat - apparently an assistance dog. These four-legged friends are trained to help people with disabilities or illnesses or to provide emotional support - even on airplanes.

He was told by Delta support that this was possible and that he could be moved for one of the assistance dogs. The airline's website states that service animals, such as assistance dogs, are not allowed to occupy a seat or interfere with another customer's seat in any way. They are allowed to sit on the lap, in the footwell or in the adjacent footwell if an additional ticket has been purchased for the seat.

Apparently a minor booking error, which the passenger was nevertheless annoyed about: "There's no way this dog has spent as much time with this airline as I have," said "ben_bob".