The world’s busiest airport ground to a standstill on Sunday, as a sudden and severe power outage grounded more than 1,000 flights at Atlanta’s Hartfield-Jackson International Airport.

After spending a few hours grappling with the problem, authorities at the airport expressed confidence that the problem would get solved by midnight, and that the electricity would be back on.

The trouble began around one o’clock Sunday afternoon, when the lights in the airport suddenly went out. The airport immediately canceled all outgoing flights, while arriving flights were held at their point of departure, and international flights were diverted.

According to a statement from Georgia Power, “No personnel or passengers were in danger at any time.”

The utility company also said that a fire in an underground electrical facility might have caused the fire.

Jeff Smith, 46, of Pittsburgh, was stuck on the tarmac for three hours after his plane landed. Smith told the Associated Press, “This is the worst experience I’ve ever had at an airport.”

According to the AP, “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 AP further explained, “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 traveling 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.”

Hartsfield-Jackson, the world’s busiest airport since 1998, serves over 100 million passengers a year.

According to the official airport website, Hartsfield-Jackson services 2,500 arriving and departing aircraft each day.