The power outage that darkened Atlanta's airport and a snowstorm that buried the South combined in December to cost Delta Air Lines US$60 million in pre-tax income, airline executives said Thursday.

Winter Storm Benji blanketed much of the South with snow during several days, creating numerous travel problems in a region that isn't typically prepared to remove it.

The power outage Dec. 17 shut down the airport for most of a Sunday, as primary and backup lines that travel underground through the same tunnel were knocked out by a fire. Delta spent several days recovering at its headquarters hub at the world's busiest airport, which has 100 million annual passengers.

The events combined to cancel 2,900 flights for the airline that prided itself on avoiding a mainline cancellation for 242 days last year and for 90 of those days without a cancellation among its regional airline partners.

The outage cost the airline US$40 million and the storm cost US$20 million, CEO Ed Bastian told investors and reporters Thursday on an earnings call.

"I want to thank the Delta people for their incredible work in taking care of our customers, while recovering from these difficult events," Bastian said. "Once again, they demonstrated that our people and our culture are Delta's strongest competitive advantage."

Bastian said the airline has had "very productive conversations" with Georgia Power, Hartsfield-Jackson Atlanta International Airport and city officials about "making certain that we learn from the experience"with the right short-and long-term solutions for reliable power.

Having said earlier that Delta will try to recover costs of the outage from the airport and utility, Bastian said Thursday that "we'll have those conversations at the appropriate time with those parties."