US Aviation Market Data Insights

Find answers to your questions about the US aviation market, with flight data insights and analysis powered by OAG's Schedules Analyser.

• Which are the top airlines in the USA?
• What's the country's busiest airport?
• Which US domestic flight route is busiest?
• Is there more domestic or international capacity in the US aviation market?
• Exclusively available to download: US monthly airline seats data from 2019-present day.

The data is updated monthly. Seats are calculated as departing seats (one-way).

• American Airlines remains the biggest carrier in the US this month with 21% of the market, 22.5m seats.
• Delta Air Lines and SouthWest Airlines remain a close second and third largest, with 19% and 18% share respectively again this month.
• Spirit Airlines decreased capacity significantly again this month by 24% vs June 2024. Spirit has streamlined its network focusing on high demand, high yield routes and a significant number of its Airbus A320neo family aircraft remain grounded due to problems with Pratt & Whitney’s geared turbofan (GTF) engines.
• Frontier Airlines also reduced capacity this month, by 11%, due to a combination of economic challenges and weakened travel demand.
• Allegiant Air increased its capacity the most among the Top 10 airlines, growing by 13%.
  
  
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• United Airlines added the most seats again this month, increasing seats by 1.2m vs June 2024. Delta Air Lines increased capacity by 785,000 seats this month and American by 640,900 seats compared with June 2024.
• Cathay Pacific increased capacity at the fastest rate of 48%, 35,000 additional seats.  This reflects an increase in frequency of its routes and the introduction of the Hong Kong - Dallas Fort Worth route.
• Breeze Airways continued its growth trend, increasing capacity by 44%, 225,000 additional seats vs last year.
  

• The busiest route remains New York JFK to Los Angeles with 296,300 seats, an increase of 13% capacity vs June 2024.
• Capacity grew at the fastest rate on the Los Angeles to Chicago route, growing by 19% vs June 2024.
• There was a 12% increase in capacity on the Los Angeles to San Francisco route vs June 2024, following a similar increase last month.
• Capacity between Atlanta and Fort Lauderdale decreased, with 32,700 fewer seats - a reduction of 13% vs June 2024.
• There was a 12% decline on the Honolulu to Kahului route, a reduction of 32,200 seats.
  

• Overall capacity in June 2025 increased by 2% vs last year, an additional 1.9m seats.
• The state of Illinois saw the largest increase in seats, with capacity increasing by 385,000 seats vs June 2024.
• Percentage wise capacity increased most in Michigan and Tennessee, both up by 9%, followed by the District of Columbia, with an increases of 8%.
• Capacity decreased by 179,700 seats in North Carolina and 108,700 in Hawaii vs last year.