ATLANTA — A power failure at Hartsfield-Jackson Atlanta International Airport on Sunday disrupted operations at the busiest airport in the world, forcing the cancellation of more than 1,150 departing or arriving flights and stranding travelers on planes on the tarmac for hours, the authorities and passengers said.

The power failure at the airport, a major hub for domestic and international flights, sent a ripple of disruptions across the country, affecting flights in Chicago, Los Angeles and elsewhere. There were signs the problems would linger into Monday, as Delta Air Lines announced Sunday evening that it planned to cancel 300 flights the next day.

Many flights in the air were diverted when the power went out, and the United States Customs and Border Protection said on Twitter that international flights destined for Atlanta were rerouted to other airports.

Georgia Power, the utility provider for the airport, said early Sunday evening that the failure, which occurred around 1 p.m., might have been caused by a fire that damaged an underground electrical facility and cut power to a substation serving the airport. It also damaged a backup system that provides power to the airport in emergencies.