One plane passenger had an eventful flight after finding that their seat was occupied by a massive dog.

I would say that I’ve never had a problem on a plane, but on my last flight, I boarded to find someone already in my seat…

I had booked that window seat and they refused to move… but at least it wasn’t a giant dog.

A United Airlines passenger has expressed outrage on a Reddit post after being moved from their seat due to a large service dog.

This incident occurred on a United Airlines fault. Credit: JanJBrand/Getty

“Totally absurd that an oversized dog can displace a paying passenger from their seat,” the frustrated flyer wrote in the post that has since gone viral.

The incident reportedly occurred as the passenger boarded a flight to Denver.

To their surprise, they found an “enormous ‘service’ dog” occupying their assigned seat, as documented in a photo accompanying the post.

“He was way too big to fit on the floor,” the Redditor noted, adding that their attempt to alert a flight attendant yielded little sympathy.

“The flight attendant was a few rows away and when asked if she saw the dog, she just shrugged,” the passenger recounted.

Efforts to address the situation with the dog’s owner also proved unsuccessful. The passenger explained that the animal, described as being too large to fit under a seat, left the crew with limited options on the full flight.

Ultimately, the passenger was reassigned to another seat, while the oversized canine remained in the original spot for the duration of the journey.

The passenger was displaced by the dog. Credit: Sparkling_Spritzer/Reddit

Being displaced in favor of a four-legged traveler left the passenger seething.

“United needs to crack down on passengers abusing the ‘service’ animal allowance,” they stated. “How can someone be allowed onboard with a dog that big without buying an extra seat?”

The flyer cited United Airlines’ own policy, which stipulates that service animals must “sit in the floor space” in front of their owner’s seat and cannot block aisles or encroach on neighboring passengers’ spaces.

“It is nasty to have a dog outside of a carrier sitting on passengers’ seats with his butt on the armrests,” they wrote.

“The gate agents carefully check the size [of] my carry-on, but apparently they don’t monitor the size of people’s ‘service’ dogs! WTH.”

Comments flooded in, with many siding with the outraged Redditor.

“Dude should be kicked off the flight if he didn’t pay for an extra ticket for his dog,” one person said, as a second added: “Service dogs are required to sit on the floor at the passenger’s feet. Not on a seat. This is for the animal’s safety since it can’t wear a proper seatbelt. Total bullsh*t from United not enforcing this.”

Another comment read: “Hi [United] crew here, all service animals must fit with in the space of the floor. It’s against our policy to have any animal service or not on any pax’s seat so everyone was wrong here. Sorry that happened to you.”

I like dogs, but even I’d be a bit annoyed at this.