A passenger has gone from the elation of being upgraded to the devastation of being downgraded within minutes - but was left even more furious after realising 'who' was in his seat. Taking to Reddit to share his anger, the traveller posted a photo alongside a lengthy caption detailing his experience on a recent Delta Air Lines flight in the US. "I got upgraded to first this morning, only to 15 mins later get downgraded (to a worst seat than I previously had).

I asked the desk agent what was going on and she said "something changed"," he wrote. READ MORE: Cheap domestic flights on offer in Webjet's boxing day sale While he says he was initially "disgruntled", he then became "livid" after boarding the plane to discover a dog was in his first-class seat. "I immediately chat Delta support and they say "you may be relocated for service animals" and there is nothing they can do," he continued.

"There is no way that dog has spent as much with this airline as I have ...

What an absolute joke." READ MORE: Five reasons why the Philippines should be your next family holiday destination The traveller went on to question his loyalty to the airline, and his post sparked a lengthy discussion garnering over 1200 comments. "It's a dog eat dog world," one person mused.

Others said they thought having animals on planes was "getting out of hand". "And don't even go there with "it's a service animal". Stay home or drive if you need your pet that bad," one person wrote.

Anothe.