Chicago O’Hare Airport (ORD) is one of the most important hubs in the United States of America, with its relatively central location making it a perfect fit for both domestic and international routes. It is also one of the country’s busiest airports, and, during the first half of 2026, it even has more scheduled flights than the bustling hub that is Atlanta (ATL). As such, it’s little wonder that United and American are fighting so hard for market share.