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.

Here are some highlights from this month's US market data:

• Largest airline: American Airlines (21.3m seats)
• Busiest airport: Atlanta Hartsfield-Jackson (5.2m seats)
• Busiest US domestic flight route: New York JFK to Los Angeles (302,700 seats)
• State adding most airline capacity: Florida (+371,700 seats)

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

• American Airlines remains the biggest carrier in the US in December 2025 with 21.3m scheduled airline seats, which represents 21% of the market.
• Southwest Airlines and Delta Air Lines represent 19% and 18% share of the market respectively, with 19.3m and 18.8m scheduled airline seats.
• Spirit Airlines decreased capacity by 33% vs December 2024, with 1.24m fewer scheduled airline seats.
• The Big 4 (American, Delta, United, and Southwest Airlines) represent 74% of the total US market.
                                                   
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• American Airlines added the most seats this month, increasing seat capacity by 801,800 vs December 2024. United Airlines follows with the second-largest capacity increase of 669,300 seats.
• Percentage-wise Breeze increased seat capacity at the fastest rate of 43% vs December 2024, followed by Cathay Pacific with a 41% increase.
  

• Once again, New York JFK to Los Angeles is the busiest route in the US this month, with 302,700 seats available - an 8% increase in capacity compared to December 2024.
• The Atlanta to New York LaGuardia route saw the largest percentage growth this month, with capacity rising 15% to 250,400 seats.
• Seat capacity saw the largest decreases on the Las Vegas to Los Angeles route (down 14%) and the Honolulu to Kahului route (down 13%) compared to December 2024.
• Honolulu to Los Angeles has displaced Los Angeles to Chicago in the Top 10 rankings, taking it to 11th position.
  

• Florida experienced the largest volume increase in airline seats this month, adding 371,700 compared to December 2024 - a 3% rise in capacity.
• Percentage-wise capacity in Tennessee increased most again, up by 13% this month.
• Nevada saw the largest drop in airline seat capacity this month, down by 235,500 seats - a 7.4% decrease. California followed with 147,400 fewer seats than last year, a reduction of 1.2%.
  

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).