US aviation market data

US aviation market at a glance

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

• Largest airline: American Airlines (22.1m seats)
• Busiest airport: Atlanta Hartsfield-Jackson (5.4m seats)
• Busiest US domestic flight route: New York JFK to Los Angeles (310,100 seats)
• State adding most airline capacity: Illinois (+776,300 seats)

Top 10 biggest US airlines by seats

• The Big Four (American Airlines, Delta Air Lines, United Airlines, and Southwest Airlines) represent 75% share of the market in April 2026.
  
• American Airlines remains the biggest carrier in the US with 21% of the market, operating 22.1m seats.
• Delta Air Lines and Southwest Airlines represent 19% and 18% share of the market respectively, with 19.5m and 19m seats.
  
• Spirit Airlines has decreased capacity by 36% year-on-year with 1.3m fewer seats.

Top 10 US airlines adding capacity year on year

• United Airlines recorded the largest year-on-year capacity growth this month, adding 1.2 million seats compared with April 2025. American Airlines made the second largest, increasing capacity by 678,300 seats versus last year.
• Percentage-wise, Breeze continues to increase capacity at the fastest rate of 42% vs April 2025, followed by Cathay Pacific with 39% more capacity. Cathay Pacific's capacity increase reflects both the introduction of new routes (e.g. SEA) and increased frequency (e.g. DFW) as the transpacific market continues to fully rebound post-COVID. 

Top 10 busiest airline routes in the US

• The busiest airline route in the US this month is New York JFK to Los Angeles with 310,100 seats, an increase in capacity of 9% vs April 2025.
• Los Angeles to San Francisco is the second busiest route with 299,300 seats, a 7% increase in capacity year-on-year.
• Atlanta to Fort Lauderdale recorded the largest percentage growth in capacity, up 34% versus April 2025, with 72,600 additional seats.
• Capacity decreased most on the Las Vegas - Los Angeles route, declining by 11% vs April 2025.
  

Top 10 busiest US airports

Top 10 airports by departing seats (one-way) this month 

• Atlanta remains the biggest airport in capacity terms, with 5.4m seats - 5% share of capacity.
• Chicago O'Hare saw the largest increase in capacity again this month, adding 720,600 more seats vs April 2025 to 4.8m seats. In addition to the intense competition between United Airlines and American Airlines, this continued increase in capacity reflects strong business travel demand and the long-term airport expansion.
• Las Vegas decreased capacity most within the Top 10 again this month, with 211,800 fewer seats than last year.

US states adding & removing most capacity this month vs same month last year

• The state of Illinois continued to see the largest increase this month, with 776,300 additional seats vs April 2025, resulting in almost 15% more capacity than last year. This reflects the ongoing growth in capacity at Chicago O'Hare.
• Nevada recorded the largest capacity decline this month, with 226,200 fewer seats, a 7% reduction year on year. This is followed by Arizona with 104,400 fewer seats vs last year.
  

Total US flight capacity by month, domestic & international

To view US flight capacity statistics from 2019-2026, 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).

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