Bastian said the airline may have lost $25 million to $50 million of revenue as a result of the power outage that hit the world's busiest airport on Sunday. That doesn't include additional costs incurred by Delta, which canceled 1,400 flights and is reimbursing passengers for Sunday night hotel stays.

"We have a lot of people at the start of the business week that didn't take their trips" because of the outage, Bastian said.