A British man trying to fly from Germany to his home in Essex, UK somehow boarded the wrong flight and ended up in Las Vegas, despite his boarding pass being checked multiple times by airline staff.
And the expectant father said he was treated "like a criminal" when he wound up without a visa at Las Vegas airport.
Finance broker Samuel Jankowsky, 29, who was in Germany for a work trip, boarded what he thought was a Eurowings flight from Cologne to London Stansted airport after airline staff checked his ticket — which clearly shows London Stansted as the destination airport — three times.
The first he knew he was on the wrong flight was when he woke up from a nap and looked at the flight tracker on the in-flight entertainment screen, which showed his plane flying past the UK and towards the United States.
"When I got on the plane I did think it was a big plane for a short flight, but I didn't worry about it. I put on my headphones and went to sleep," Jankowsky told MailOnline.
"When I woke up I saw that we had passed the UK. I asked the person next to me what was going on and he said, 'We're flying to Vegas'.
"I said: 'Oh f**k! Can we turn the plane around?' I didn't even know Eurowings flew to Las Vegas."
Jankowsky said he used the on-board Wi-Fi to frantically message his pregnant wife Monique, with whom he has two other children.
But things got even more complicated when he landed at Las Vegas' McCarran International Airport, where he said US immigration officers threatened to detain him.
"I was treated like a person who tried to enter the US without a visa," he said.
"The official said we had an hour to do the paperwork to put me on a flight back to Cologne.
"If I missed the flight, I'd be detained until Tuesday [four days later] when there was another Eurowings flight.
"I had a boarding pass for London Stansted which cost around 120 euro (A$180). They seemed to think I had sneaked onto the plane to get a flight to Vegas on the cheap.
"They even put me in a little cell and completely searched me. I was supervised the whole time I was there."
Jankowsky was eventually allowed to fly back to Cologne but said he "wasn't treated well" by airline staff.
"The crew were professional but they treated me like they had a criminal on the plane, maybe a serial killer," he said.
Once back in Cologne, Jankowsky said he had to travel to Mannheim to fly back to Britain.
He arrived home in Essex two days later than he was meant to, and about $1300 out of pocket for food, a hotel and his flight home.
"How could I have boarded the aircraft without a valid boarding pass for that flight? Staff checked my boarding pass three times. It shows the ineptitude of Eurowings staff," he said.
"Heaven forbid my intentions were not good. This is a major security failing."
But he acknowledged there was a funny side to the situation.
"When I told my sister she just burst out laughing for ten minutes straight," he said.
"I think they could make a movie out of what happened to me. Like The Hangover, where the main character wakes up on a flight headed to the party capital of the world."
A spokesman for Eurowings attributed the incident to an error by a service provider employee and said the incident had been resolved.