The United States is home to 672 airports offering scheduled commercial services, but a significant portion of air travel activity is concentrated in just ten locations. Together, these ten busiest airports account for approximately 35% of all flights in the country. As demand for air travel is projected to increase by around 2% in 2025 compared to 2024, the bustling nature of these airports is evident. Data from OAG sheds light on which airports ranked highest in terms of available seats for the summer of 2025.
Rankings of the Busiest Airports
1. Hartsfield–Jackson Atlanta International Airport (ATL) tops the list with over 38.1 million seats available during summer 2025. Recognized as the world’s busiest airport in recent years, ATL processed more than 108 million passengers in 2024. The airport serves as a major hub for Delta Air Lines, which holds a commanding 74% market share. Flights from ATL span the globe, including destinations such as Johannesburg OR Tambo International Airport (JNB).
2. Chicago O’Hare International Airport (ORD follows closely, with more than 31.3 million seats available. This airport is a primary hub for both American Airlines and United Airlines, offering extensive domestic and international routes. While ORD has yet to surpass its pre-pandemic peak of 84.6 million passengers in 2019, it remains a vital player in the air travel landscape.
3. Dallas/Fort Worth International Airport (DFW) ranks third, boasting over 30.7 million seats. DFW serves as the largest hub for American Airlines, which holds over 66% market share. The airport experienced a record year in 2024, processing more than 84 million passengers, with expectations for 2025 to exceed that figure.
4. Denver International Airport (DEN) is the fourth busiest, with more than 29.7 million seats available. As the primary hub for United Airlines, DEN saw significant passenger traffic last year, processing over 82 million passengers. Its longest runway, measuring 3.03 miles, is the longest commercial runway in the U.S.
5. Los Angeles International Airport (LAX) ranks fifth with 27.1 million seats. It stands as the busiest airport in California and a major hub for all three major legacy carriers: Delta, United, and American Airlines. Last year, LAX’s busiest international route was to London Heathrow (LHR), with over 1.6 million passengers.
6. John F. Kennedy International Airport (JFK) holds the sixth position with 23.6 million seats. Known as a primary international gateway, JFK serves numerous international carriers, including Emirates and Virgin Atlantic. The airport is also home to the world’s longest nonstop commercial flight to Singapore Changi Airport (SIN).
7. Harry Reid International Airport (LAS) in Las Vegas is seventh, with over 20.3 million seats. Southwest Airlines dominates operations at LAS, holding more than 40% market share. The airport welcomed over 58 million passengers in 2024, marking its highest annual total.
8. Charlotte Douglas International Airport (CLT) ranks eighth with a total of 20.1 million seats. As a major hub for American Airlines, which commands a 70% market share, CLT offers a variety of domestic and international flights, including services to London Heathrow (LHR) and Madrid Barajas Airport (MAD).
9. San Francisco International Airport (SFO) comes in ninth, also with over 19.6 million seats. This airport is a significant hub for United Airlines, which accounts for nearly 50% of all flights. The busiest domestic route from SFO is to Los Angeles International Airport (LAX), with over 1.3 million passengers.
10. Seattle-Tacoma International Airport (SEA) rounds out the list with approximately 19.6 million seats available. SEA serves as a crucial hub for both Alaska Airlines and Delta Air Lines, with the two airlines commanding a combined market share of over 75%. Popular destinations from SEA include Los Angeles International Airport (LAX) and Phoenix Sky Harbor International Airport (PHX).
As airlines and airports adapt to the growing demand for air travel, these ten facilities will continue to play essential roles in connecting passengers across the globe. The data from OAG not only highlights the busiest airports but also reveals the evolving landscape of the aviation industry as it moves toward recovery and growth in the coming years.
