Some travelers were headed to weddings, some to funerals. Others were leaving for a Disneyland Paris vacation, taking a business trip to Britain, returning home from a honeymoon in Italy or moving to Australia.
Instead, on Friday, they found themselves sitting on airport floors, riding on buses or checking in to hotels as tens of thousands of passengers were stranded — unable to reach their destinations because of a power outage that shut down Heathrow Airport.
“It’s a crazy situation,” said Roxanna Bagherzadeh, who was missing Persian New Year’s celebrations with her family in London because her flight from New York never took off.
Some flights were rerouted midocean for Madrid or Montreal. Others were forced to turn back entirely. American school trippers were being held in London. Musicians worried they would miss their performances. Some travelers took circuitous detours across Europe to reach their families. Others had to give up on big plans.
“I was going to propose,” said Kevin Black, a bass player touring Europe with his band who was supposed to be joined by his girlfriend. But her flight turned around and took her back to Nashville.
“It was going to be on one of the bridges overlooking the river at sunset” in Paris, Mr. Black said of his planned proposal on their European trip. Now, he said, “it will probably be at a waterfall in Tennessee. What can I do?”
With airlines struggling to respond to huge amounts of requests, many passengers could not get through to them. Flights for the next few days quickly booked up, and the only ones left had exorbitant prices, travelers said.
The outage also came as many Americans were starting their spring break, disrupting family plans.
“Instead of fish and chips we have crying children at home,” said David Mahler, 47, who was flying with his wife and 11-year-old twin boys to London from Los Angeles when their flight was turned around over Colorado. They were now back home looking for other options for spring break, he said, but international flights had become too expensive. “We are kind of stuck,” he said.
While passengers at London’s second-largest airport, Gatwick, which received many flights that had been headed to Heathrow, stood in long lines at help desks. Heathrow, which is usually one of the world’s busiest airports, was deserted. The drop-off zone at Terminal 3 was silent, and runways and airline counters were empty.
A teacher who had been trying to get home to Dallas tried walking between terminals when the bus she was on was not allowed to enter Heathrow. Another traveler, Monel Bailey, tried to walk to the terminal along the highway with his bags when his Uber was stopped by police officers blocking the route to the terminal. It was “a scene of chaos,” Mr. Bailey said.
The power outage, caused by a fire at an electrical substation near Heathrow, forced the authorities to close the airport for most of Friday. While some flights were set to resume later Friday, airline officials warned that travel disruptions could last for days.
A glance at Heathrow’s flight information board on Friday morning gave a sense of how big the shock waves from the closure would be. Flights from Brunei, India and Vietnam were scheduled to land, and passengers had been expecting to board planes to dozens of destinations: Miami, Singapore, Tokyo … the list went on.
Rachel Morris was eagerly waiting for her sister to join her in Philadelphia for her bridal shower on Saturday, but her flight from London was canceled. “I am devastated,” Ms. Morris said. “She is my maid of honor and my best friend and she planned the entire thing.”
Stephen McCray was stranded in London, where he had traveled from Seattle for a book tour for his wife’s debut horror novel.
“We want to get home,” Mr. McCray, 36, said. “Our dogs are waiting for us.”
Travelers took to social media to complain about the disruption and beseech the airlines for help. One wrote that he had had to pull out of a Pokémon Go championship, another that she could no longer run in a half-marathon for which she had trained.
“Sad to miss it,” said the half-marathon runner, Samira de Blij, who had been planning to fly from Amsterdam for the race in Reading, west of London, on Sunday.
Ms. Bagherzadeh posted on TikTok what she called “the saddest travel vlog of all time.” In it, she sat on the plane, took the first step of her in-flight skin care routine and braided her hair so it wouldn’t get messy on the flight.
“It was all for nothing,” she said on a phone call.
Ms. Bagherzadeh, 27, had intended to have dinner with her grandmother, who had traveled to Britain from France for the occasion. Instead, she sat on a plane on the tarmac for two hours before disembarking and returning home.
“I had a quick cry, because I wanted to see my mom,” Ms. Bagherzadeh said.
Dozens of airlines fly to Heathrow from about 180 cities worldwide. Many planes already in the air were forced to divert elsewhere when the airport closed. John F. Kennedy International Airport in New York had the most flights scheduled to arrive at Heathrow on Friday; some were diverted to Manchester, in northwestern England; to Glasgow; or to Reykjavik, Iceland.
As many as 290,000 passengers traveling in or out of Heathrow could be affected by the closure, according to Cirium, an aviation analytics company. On Friday, 669 flights were scheduled to take off from Heathrow, Cirium said.
Heathrow is the main hub for British Airways, which said that it was redirecting flights to other airports in Britain when possible.
At Fiumicino Airport in Rome, dozens stood in line at the British Airways counter, including a group of high school students from Arizona who had planned to fly home via Heathrow after a week in Italy.
Among the chaos, panic and frustration, some still tried to look at the upside.
Marilyn Leblanc said she was flying from Boston to Dublin when the pilot announced that because of the fire at Heathrow they would be heading back. But because the plane needed refueling, they were diverted to Canada for fuel.
“So we left Boston at around 7 p.m. Thursday night and arrived back Friday morning at 5 a.m.,” Ms. Leblanc said. “Just a nice Sunday drive around the ocean!”
Reporting was contributed by Nicholas Yong from Singapore; Jonathan Wolfe and Lynsey Chutel from London; and Matthew Mpoke Bigg from Rome.