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?
• And more.

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, 22.3m seats.
• Delta Air Lines and Southwest Airlines remain a close second and third largest, with 19% and 18% share respectively.
• The Chapter 11 filing from Spirit Airlines is reflected in a further capacity decrease this month of 23% vs May 2024, a reduction of 1.1m seats, as they reorganise their network.
• Frontier Airlines also reduced capacity this month, by 13%, 480,800 seats.
• Percentage wise Allegiant Air continued to add most capacity within the Top 10, up by 17%.
  
• 

• United Airlines added the most seats again this month, increasing seats by 1.3m vs May 2024. Delta Air Lines increased capacity by 751,200 seats again this month, having added a similar amount last month compared with May 2024.
• Breeze Airways continued its growth trend, increasing capacity by 56%, 245,400 additional seats vs last year.
• Allegiant Air made the second large percentage increase in capacity of 17%, 271,300 seats.
• Spirit Airlines and Frontier Airlines reduced capacity most, by 1.1m and 480,800 seats respectively.
  

• The busiest route is New York JFK to Los Angeles with 298,900 seats, an increase of 13% capacity vs May 2024.
• Capacity grew by 10% on the Los Angeles to San Francisco route vs May 2024, making it the third busiest domestic route.
• Capacity between Denver and Las Vegas continued to reduce this month, by 16% vs May 2024, 46,300 fewer seats.
• Capacity also reduced by 11% on the Denver to Phoenix route taking it from the first to sixth busiest route this month.
• Capacity between Atlanta and New York La Guardia decreased, with 31,500 fewer seats - a reduction of 12%.
  

• Overall capacity in May 2025 increased by 2% vs last year, an additional 1.7m seats.
• The state of California saw the largest increase in seats again this month, with capacity increasing by 513,100 seats vs May 2024.
• Percentage wise capacity increased most in Indiana, up by 12%, followed by Tennessee and the District of Columbia, with increases of 10% and 9% respectively.
• Capacity decreased by over 150,000 seats in both North Carolina and Texas.