The latest data from OAG highlights the dominance of the United States in the global aviation market, with over 92 million seats available in October 2025. This figure represents a significant 27% increase compared to China, which ranks second with around 72 million seats. Understanding the dynamics of this market involves examining the most popular airline routes, utilizing insights from Cirium, an aviation analytics company.
The following are the ten most popular airline routes in the U.S. for October 2025, ranked by seat availability, along with their market share by airline and year-over-year comparisons.
10. Denver to Las Vegas
The route from Denver International Airport to Harry Reid International Airport in Las Vegas offers 239,000 seats this month, a 4% decrease from 2024. Three airlines operate this route, with Southwest Airlines holding the largest market share at 40% due to its eight daily flights in both directions. The decline in capacity is partly attributed to Spirit Airlines discontinuing service to Denver last year.
Market Share:
– Southwest Airlines: 40%
– United Airlines: 35%
– Frontier Airlines: 25%
9. Denver to Chicago O’Hare
In ninth place, the route from Denver to Chicago O’Hare International Airport offers 243,000 seats, marking a 2% increase compared to last year. United Airlines dominates this route, operating ten flights daily and controlling nearly two-thirds of the market.
Market Share:
– United Airlines: 61%
– American Airlines: 19%
– Southwest Airlines: 12%
– Frontier Airlines: 8%
8. Honolulu to Kahului
The inter-island route from Honolulu International Airport to Kahului Airport is notable for having the highest number of flights in the U.S., with 1,272 services scheduled for October. Despite this, it ranks eighth in seat availability at 248,000, experiencing a 12% decrease since last year, largely due to reduced flights by Southwest Airlines.
Market Share:
– Hawaiian Airlines: 66%
– Southwest Airlines: 34%
7. Los Angeles to Las Vegas
Connecting two major cities, the Los Angeles to Las Vegas route offers 261,000 seats in October, down 14% from 2024. This route is served by eight different airlines, with Southwest Airlines leading at 24% market share. The reduction in capacity reflects a decline in visitor numbers reported by the Las Vegas Convention and Visitors Authority.
Market Share:
– Southwest Airlines: 24%
– Delta Air Lines: 19%
– United Airlines: 17%
– American Airlines: 13%
6. Atlanta to Orlando
The Atlanta to Orlando route remains a vital air corridor, offering 262,000 seats, which is 9% lower than last year. Delta Air Lines holds a commanding 66% market share, operating nearly thirty flights daily.
Market Share:
– Delta Air Lines: 66%
– Frontier Airlines: 17%
– Southwest Airlines: 14%
– Spirit Airlines: 5%
5. Atlanta to New York LaGuardia
This route provides 263,000 seats in October, reflecting a slight 1% increase from 2024. Delta also dominates this route, operating up to 15 return flights daily, while Southwest and Frontier provide competitive services.
Market Share:
– Delta Air Lines: 63%
– Southwest Airlines: 14%
– Frontier Airlines: 13%
– American Airlines: 10%
4. Denver to Phoenix
The Denver to Phoenix Sky Harbor International Airport route ranks fourth with 280,000 seats, showing a strong 7% growth compared to last year. This route is characterized by competition among airlines, all of which have a hub at one of the two airports.
Market Share:
– Southwest Airlines: 42%
– United Airlines: 27%
– Frontier Airlines: 20%
– American Airlines: 10%
3. Los Angeles to San Francisco
Linking two of California’s largest economic hubs, the Los Angeles to San Francisco route offers 288,000 seats this month, which is a 10% decrease since 2024. United Airlines leads with a 35% market share, reflecting the competitive nature of this critical business route.
Market Share:
– United Airlines: 35%
– Delta Air Lines: 24%
– Southwest Airlines: 13%
– American Airlines: 11%
2. New York JFK to Los Angeles
The transcontinental route between New York’s JFK and Los Angeles ranks second with 307,000 seats, up 9% from last year. This route serves a diverse mix of passengers, with Delta Air Lines leading at 43% market share, primarily using widebody aircraft for enhanced passenger comfort.
Market Share:
– Delta Air Lines: 43%
– JetBlue: 31%
– American Airlines: 22%
– Frontier Airlines: 5%
1. New York LaGuardia to Chicago O’Hare
Topping the list, the route from New York LaGuardia to Chicago O’Hare offers 320,000 seats, a 13% increase from 2024. This route sees competition among the major airlines, with United Airlines leading at 46% market share.
Market Share:
– United Airlines: 46%
– American Airlines: 29%
– Delta Air Lines: 21%
– Spirit Airlines: 5%
The analysis reveals how airline routes are shaped by factors such as demand fluctuations, seasonal changes, and competitive strategies among airlines. The insights provided by Cirium offer a comprehensive overview of the evolving landscape of U.S. air travel.
