United Airlines carried 182 million passengers in 2025, which was equivalent to 499,000 passengers daily. According to the US Department of Transportation, this was the Star Alliance member’s best year yet. Traffic surpassed the prior high, held in 2024, by 5%.

Assuming a minimum of 1,500 passengers, the source shows that United had 1,047 routes. Some 721 were domestic, while 326 were international. The airline transported 143 million domestic passengers, accounting for 79% of the total traffic.

United’s 15 Routes With One Million Passengers Or More

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The top five markets in 2025 were Newark-San Francisco (1.53 million two-way passengers), Chicago O’Hare-San Francisco (1.40 million), Denver-Houston Intercontinental (1.38 million), Denver-Chicago O’Hare (1.34 million), and Newark-Los Angeles (1.34 million)

The rest of the 15 most-trafficked airport pairs were Newark-Chicago O’Hare (1.33 million), Chicago O’Hare-New York LaGuardia (1.31 million), Houston Intercontinental-Chicago O’Hare (1.21 million), Denver-San Francisco (1.17 million), Houston Intercontinental-San Francisco (1.16 million), Los Angeles-Chicago O’Hare (1.15 million), Newark-Orlando (1.14 million), Houston Intercontinental-Los Angeles (1.04 million), Newark-Houston Intercontinental (1.04 million), and Newark-Denver (1.02 million).

You’d expect a hub to be on one end of each of those airport pairs. But 13 of the 15 markets had a hub at both ends too, with Chicago O’Hare-New York LaGuardia and Newark-Orlando being the only exceptions. Of course, as all eight airports also serve major cities or tourist destinations, it’s hardly surprising. United’s widebodies are deployed on hub-to-hub routes.

United’s Most-Trafficked Market Last Year

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With 1.53 million passengers, Newark-San Francisco was the Star member’s most-trafficked market last year. It always is. Analysis of DOT data shows that 2025 was United’s fifth-best year to date on the route, after 2019 (1.76 million), 2017 (1.60 million), 2016 (1.60 million), and 2018 (1.59 million).

United filled 88.5% of its available seats last year, which was down by two-and-a-half percentage points from 2024. Of course, seat factor is just one performance measure, and should not be considered in isolation. It is always about how it was achieved. According to Cirium Diio data, the carrier flew five types/variants: the Boeing 757-200, 777-200, 777-200ER, 787-9, and 777-300ER. Across the whole year, widebodies operated nearly half of the flights (46%).

The airline’s 1.53 million passengers included everyone: those who only flew between the two airports, those who connected to another flight in Newark, those who transited in San Francisco, and passengers who transferred at both hubs. The DOT suggests that 1.16 million of these passengers were local, while the remaining 367,000 connected.

Booking data suggests that six in ten of the 367,000 passengers who connected did so in San Francisco. Newark-Hong Kong was the top segment (United’s nonstop flights existed until 2020), followed by Shanghai Pudong, Honolulu, Taipei, Melbourne, Manila, Seoul Incheon, Sydney, Singapore, and Kahului.

The remaining four in ten passengers transited in Newark. The most popular markets were San Francisco-Tel Aviv (United’s nonstop flights existed until 2023), San Juan, Boston, Lisbon, Dublin, Burlington, Delhi, Madrid, Portland (Maine), and Johannesburg. United begins nonstop San Francisco-Portland flights this year.

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United’s #1 Route Without A Hub At One End

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With 1.31 million passengers, Chicago O’Hare-New York LaGuardia was United’s most-trafficked market with only one hub at either end. It was the carrier’s seventh-busiest route out of the 1,047 airport pairs served last year. Given how important this route is for business travelers, it is not surprising that the vast majority of passengers—79%—were local. They did not fly elsewhere.

As United is O’Hare’s largest operator, it was comfortably the leading operator at the local level. The DOT shows that it transported 46% of the passengers, followed by American (28%), Delta (21%), and Spirit (5%). Its dominance was mainly because it had a higher frequency. There’s a close relationship between frequency and market share.

United had an average of 15 daily departures each way, against ten for American. The 179-seat 737-900ER was United’s most-used equipment, followed by the 757-200, A321neo, 737 MAX 8, 737 MAX 9, and A319.

When all airports serving Chicago and Greater New York are included, 4.10 million two-way local passengers flew last year—11,200+ daily. Given United’s hubs at O’Hare and Newark and dominance to LaGuardia, the carrier transported 1.89 million (46%), more than double American’s share (22%). The DOT suggests that this city pair alone generated ticket revenue of about $329 million for United.