The couple had calculated it would take them at least twice that long to fly to San Jose, Costa Rica (SJO). By the time they realised their mistake, the plane was already in the air and bound for San Jose, California (SJC).

Courtney Davis can sympathise. Spokesman for Sydney Airport (YQY) in Nova Scotia, Canada, she says that at least once a year, a passenger boards a plane from somewhere in the world thinking they are heading to Australia only to land at her airport and wonder why they are met by people are wearing toques and winter boots. Davis says airport staff can usually spot those passengers right away – their shorts and flip flops are a dead giveaway.

“Of course people are usually panicked and a little confused,” Davis says. “But our little island has a way of making people feel at home and welcomed.”

Milan Schipper didn’t hang around long enough to put that claim to the test. In 2017, the Dutch student arrived at the wrong Sydney and told his Canadian hosts he had booked his flight because he thought he had found a great deal. Schipper arrived with a backpack, expecting hot weather and beaches, only to find snow on the ground and a blizzard on the way. Schipper caught a flight back to Amsterdam right away, remembers Davis.

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When British travellers Emma Nunn and Raoul Christian made the same mistake, in 2002, however, the pair stayed and vacationed on the Canadian east coast. They were made to feel welcome by local tourism groups, they later told the BBC, checked out pickup trucks, visited local hockey and curling rinks, and dined on the lobster the region is famous for.

Sydney (SYD), New South Wales, might have the world-famous Opera House and Harbour Bridge, says Davis, but her Sydney is home to the world’s largest fiddle and the Seal Island Bridge.

“We don’t have a Great Barrier Reef, but we have shipwrecks that can be explored that are so rich in history, and no shortage of people to tell you their stories over a beer at a local brewery or pub.”

The world is full of places that have similar airport codes, sound the same or even, as in the case of Sydney and San Jose, are spelt exactly like an altogether different destination.

In August last year, evolutionary biologist Jake Leyhr was heading to a conference in China and was booking flights from his home country of Sweden.

“When I typed in ‘Stockholm’ into the departure field, I blindly selected the top predicted option that the website gave me,” Leyhr tells me.

It wasn’t until he was about to finalise his booking that Leyhr realised he was about to pay for a flight from Papua New Guinea. Stockholm Airport (SMP) is a tiny airstrip in the centre of the island of New Guinea, whereas Sweden’s main airport is Stockholm Arlanda Airport (ARN).

“Luckily, I caught the mistake before getting particularly close to booking anything,” Leyhr says. “How many people would have even known that Stockholm Airport was not in Sweden?”

Neuroscientist Boris Barbour, who lives in Paris, France, was once asked to give a talk in Brussels, Belgium, at a university in Louvain, also known as Leuven. In a rush at the railway station, he ran to his platform, saw the sign for Louvain on the side of the train and jumped aboard.

“When I got there, the map didn’t seem to fit where I was,” Barbour says. “I found myself on the carport and the architecture didn’t seem right. I had to ask someone for directions and it took a while for them to realise what happened.”

He had caught the train to Louvain-la-Neuve, a city 30km southeast of Brussels.

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Barbour, who managed to get to the right Leuven/Louvain before it was too late, theorises that academics are particularly prone to ending up at the wrong place when travelling to conferences and seminars.

“They’re distracted and busy people. You’re always trying to finish something off at the last minute so you can get to the destination where you’re presenting a paper.”

That is what happened to Jason Chow, a professor at Virginia Commonwealth University, in Richmond, in the United States, in June. He was scheduled to be on a panel at a mathematics conference at Carleton University, in Ottawa, Canada. In a rush, he booked a flight to Calgary, about 3,300 kilometres from his planned destination. When he arrived and tried to book an Uber to get to his hotel, he was surprised to see the map on his phone showing a cross-country journey. And a huge fare.

“Booked flights and hotels in a rush, both are Canadian cities I’ve never been to that sit nicely on the south side of a river and have similar looking night-time pictures of their respective Westins,” he wrote on Twitter. “I got Calgary and Carleton (the university where the conference is) mixed up in my head.”

British speech therapist Richella Heekin had everything right when she saved for a year and booked a 2016 trip to Las Vegas as a surprise birthday present for her boyfriend. She didn’t realise until it was too late that she had bought a ticket for a departure from the wrong continent.

“We got dropped off at the airport and looked at the board and there was no connecting flight,” she says. “There was nothing up there, no American Airlines flight so we went to the desk and there was no American Airlines.”

Heekin, who lives in the West Midlands, in Britain, thought she would be flying from Birmingham, England (BHX), to McCarran International Airport. On the online site she used to book her ticket, she says, there was nothing to indicate that the ticket she was buying was for a flight from Birmingham (BHM) in the US state of Alabama.

She was unable to get a refund for the £1,200 she had paid, but Heekin’s luck picked up when, after hearing of the mishap, Virgin Airlines and the Birmingham, Alabama tourism board paid for flights and accommodation for the couple to visit both Birmingham (BHM) and Las Vegas.

“It turned out to be one of the best mistakes I ever made,” Heekin says.

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Even experienced travel agents, and people you never want to play airport code jeopardy against, can make mistakes, according to Rick Seaney, chief executive of travel advice website Fare Compare.

“I once landed in Dallas Lovefield, but I was expecting to land at DFW, Dallas/Fort Worth,” says Seaney, who explains that some frequent travellers get into automatic mode when booking; either that, or a case of “fat fingers” causes them to type LGW (London Gatwick) instead of LGA (LaGuardia, New York).

“I don’t think I’ve ever made a mistake [when booking flights for others], but I’ve caught mistakes just in time,” he says.

Langford and Lowdermilk did eventually make it to Costa Rica. When they landed at SJC, they were taken to a quiet desk by a flight attendant, who began looking for onwards flights. The airline was able to book the pair on a flight from Los Angeles to Costa Rica.

The airport they were scheduled to land in was not in San Jose, though, causing Langford further concern.

“We were landing in Liberia and I checked multiple times to make sure that was really in Costa Rica, because it did sound like a city in Europe,” Langford says. (One imagines his confusion when, on his next trip to Europe, he arrives instead in West Africa.)

The pair spent a day in San Jose, California, rented a car to drive the six hours to Los Angeles, where they boarded their plane to Costa Rica.

It was a mistake Langford says he will never make again. The error was the result of rushed online booking, he says; he had been refreshing his browser continuously to find the best deal. But after days of searching and waiting, he woke up one morning and found prices were hundreds of dollars lower than they had been the night before. He booked without a second thought.

“The flight attendants weren’t surprised at all. They say it happens all the time,” Langford says. “That is how I learned there were so many San Joses around the world.

“I could just travel to San Joses and end up in a new country all the time.”