After 10 years at United, CEO Scott Kirby is thinking big about the future of his airline from JFK to AI

United Airlines CEO Scott Kirby was fired from American Airlines 10 years ago and now runs the second-most profitable carrier in the U.S. He told CNBC that he wants to expand at JFK airport and is preparing for how AI will change the industry. Kirby, who has floated the idea of mergers with American and Delta Air Lines but so far been rebuffed, said he's still not interested in acquiring a smaller carrier.

Scott Kirby says he doesn't believe in revenge. "Everyone thinks I do, but no, I don't," said the United Airlines CEO, whom American Airlines fired 10 years ago, when he was president of that carrier. "I compete aggressively." United announced it had hired him as president on Aug. 29, 2016, a blink after American disclosed his departure. Now, Kirby is running the second-most profitable U.S. airline after Delta Air Lines. And his former employer, American, is a distant third of the big, more-than-century-old, U.S. carriers, though it's working to ramp up revenue through a host of upgrades, including bringing back seatback screens.

Kirby floated the idea of megamergers with both Delta and American in the past year, combinations that would bring together some of the biggest airlines in the world. He's so far been rebuffed, and antitrust experts were skeptical about the possibility. He's thinking bigger than he has before as the industry faces ever-higher costs, limited airport infrastructure and a population that's ready to shell out more to fly — often in the expensive seats — to the next "it" destination.

Kirby said he wants to expand United's footprint at New York's John F. Kennedy International Airport after his airline returns to the congested airport through a partnership with American's former partner, JetBlue Airways, as early as next year. "We got a bunch of irons in the fire to try to find ways to do it," he said, adding that United could at some point acquire slots from carriers that aren't flying profitable routes out of the airport. And while United already holds the crown among U.S. airlines for international flights, which are in high demand among U.S. tourists, he wants to expand the carrier's footprint abroad even more.

This week, United is set to announce a host of new international routes, the carrier's annual splash that has previously included new dots on the map like Ulaanbaatar, Mongolia and Bilbao, Spain. United has been touting its international expansion for years, saying its vast network acts as a driver for customer loyalty and sign-ups for lucrative travel rewards credit cards. Its route announcements typically come with much fanfare.