More than 1,000 flights were grounded on Sunday when a sudden power cut brought the world’s busiest airport to a standstill.
The outage struck Hartfield-Jackson Atlanta International Airport at around 1pm local time, stopping all outgoing flights, while arriving planes were held at the point of departure. International flights were diverted to other airports.
It took authorities at the airport in the US state of Georgia more than 10 hours to restore power after the blackout began.
The outage causes passengers huge disruption just days before the Christmas travel rush.
"A lot of people are arriving, and no one is going out. No one is saying anything official. We are stuck here," said Emilia Duca, 32, a Delta passenger on her way to Wisconsin from Bogota, Colombia. "It's a nightmare."
According to a Georgia Power statement, a fire in an underground electrical facility may have been responsible for the outage. The cause of the fire was not known.
"No personnel or passengers were in danger at any time," the statement said.
No areas outside of the airport were affected by the power loss. The utility said that there are "many redundant systems in place" to ensure the power supply to the airport and that such outages at the airport "are very rare".
That was little comfort to Jeff Smith, 46, of Pittsburgh, who said: "This is the worst experience I've ever had at an airport."
By evening, power had been restored to at least one concourse. On its Twitter page Sunday night the airport tweeted, "Power on Concourse F is back ON! We are working with great urgency w/ @GeorgiaPower to restore power throughout rest of airport." Airport workers were distributing bottled water, and Dunkin' Donuts was giving out doughnuts.
The airport later confirmed power had been restored on all of its concourses as it handed out 5,000 meals to stranded passengers.
Officer Lisa Bender of the Atlanta Police Department said officers were at the airport to help with crowd control and managing traffic around the airport.
Delta Air Lines, which has its hub at the airport, said about 900 mainline and connection flights were cancelled, and 48 flights were diverted. Delta temporarily embargoed unaccompanied minors from travelling on Monday.
At Southwest Airlines, about 70 Atlanta departures out of 120 scheduled for Sunday were cancelled, an airline spokesman said in an email. United Airlines and JetBlue Airways were among carriers reporting delays or cancellations.
American Airlines reported only a handful of diversions and cancellations because the carrier does not use Atlanta as a hub, airline spokeswoman Alexis Aran Coello.
Hartsfield-Jackson, which serves 104 million passengers a year, is the world's busiest airport, a distinction it has held since 1998.
The airport serves an average of 275,000 passengers daily, according to its website. Nearly 2,500 planes arrive and depart each day.