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, 21.9m seats.
• The gap between Delta Air Lines and SouthWest Airlines widened slightly with the former now operating 19% of seats in the market and the latter 17% this month.
• Spirit Airlines' capacity dropped significantly again this month by 28% vs Aug 24, 1.4m fewer seats.  As part of its restructuring Spirit launched Premium Perks in May 25 in line with its high value, low cost positioning and has just announced that 270 pilots will be furloughed with a further 140 Captains demoted to First Officer.
• Frontier Airlines  also reduced capacity by 8% in Aug 25.
• Percentage wise Allegiant Air continued to add most capacity within the Top 10, up by 15%.
• The Big Four carriers represent 73% share of the market.                                                   
  
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• United Airlines added the most seats again this month, increasing seats by 1m vs Aug 24.  
• Delta Air Lines increased capacity by 314,300 seats this month and Allegiant Air by 237,600 seats compared with Aug 24.
• Percentage wise, Cathay Pacific followed by Breeze Airways increased capacity at the fastest rate of 55% and 40% in Aug 25.

• The busiest route this month is New York JFK to Los Angeles with 301,900 seats, an increase of 9% capacity vs Aug 24.
• Capacity decreased most on the Anchorage to Seattle route by 13% followed by Honolulu - Kahului and Atlanta to Fort Lauderdale, both by 12%, and Atlanta to Orlando by 11% vs Aug 24.
• The Atlanta - New York La Guardia route displaced Honolulu - Los Angeles which moved to 11th position in Aug 25.

• The state of Florida saw the largest increase in seats this month, with capacity increasing by 329,300 seats vs Aug 24.
• Percentage wise capacity in Tennessee and Michigan continued to increase most, up by 8% and 6% respectively.
• Capacity decreased most in North Carolina again this month, by 384,000 seats, followed by Texas with 250,600 fewer seats vs last year.

To view US flight capacity statistics from 2019-2025, click the button below to download the data.

*As of July 2025, international capacity is reported on a two-way basis (previously one-way departing).