Chicago O’Hare International Airport (ORD) has been United Airlines’ primary hub since the mid-1950s, when the airline moved its operations from Midway Airport to the newly constructed O’Hare. Chicago O’Hare is unique in serving as a hub for two of the largest US airlines. While American Airlines has a smaller presence than United, it still maintains a significant operation at the airport.
Recently, 
United Airlines has continued to maintain its dominance at the hub over American Airlines. A report from local news outlet WGN said that a judge ruled in favor of United Airlines, rejecting American Airlines’ attempt to prevent United from taking control of five additional gates and further expanding its presence at the hub.
Gate Battle Ends In United’s Victory
This summer, 
American Airlines filed a lawsuit in Illinois circuit court against the Chicago Department of Aviation, seeking an injunction to stop the city’s plan to grant United Airlines five additional gates while taking away four of American’s gates, effective in October 2025. The airline had initially filed the case in federal court in May 2025.
American Airlines’ primary concern was that the latest set of gate allocations assigned more space to United, the airline’s principal rival at the facility, which has slowly been capturing more and more of the facility’s market share.
In the lawsuit, American argued that Chicago, acting at United’s request, initiated the gate reallocation process too early, in violation of a 2018 lease agreement negotiated by the Chicago Department of Aviation with airlines to guide the planned O’Hare expansion. In a September 25 order, Cook County Circuit Court Judge Thaddeus Wilson dismissed that argument. United Airlines president Brett Hart said in a statement seen by WGN:
“This decision is more than a legal victory, it is a powerful validation of United’s growth, investment and incredible workforce here in our hometown of Chicago.”
American Argues United Will Gain Competitively
According to the WGN report, an American Airlines spokesperson said that the early start of the gate reallocation process “will give one airline a competitive advantage from the start.” Despite this, the Dallas/Fort Worth-based carrier emphasized that it remains committed to its Chicago hub.
The airline said it will work to preserve competition at 
Chicago O’Hare International Airport, ensuring that local travelers, as well as passengers connecting through the airport from across its global network, continue to benefit from lower fares and more choices provided by the presence of two competing carriers.
Following the global COVID-19 pandemic, United Airlines concentrated on strengthening its ORD hub, while American Airlines focused on rebuilding its network across the southern United States. Nevertheless, American has expanded its presence in Chicago, adding flights and premium seating. The airline reported that it operated 20% more flights from Chicago this summer compared with the previous summer.
United Airlines Dominates At O’Hare
Chicago O’Hare has shown itself to be a highly valuable hub for airline dominance. United can fly to either coast from O’Hare with its hundreds of 737s and narrowbody Airbus jets, as well as Canada, Mexico, and the Caribbean in just a few hours. Thanks to this geographic symmetry, the network planning division is able to create precisely timed flight waves. As incoming planes arrive and travelers connect, the same jets take off onto fresh spokes with new passengers.
According to data provided by the aviation analytics company Cirium, these are the top five airlines ranked by the number of departures scheduled for September 2025 out of Chicago O’Hare.
United Airlines led in flight operations at Chicago O’Hare in September, with 17,436 flights and 2,128,086 seats offered. Closely following was American Airlines, with a total of 12,743 flights scheduled during the month. The third-busiest carrier at ORD was Delta Air Lines, with 1,168 flights in September.
