If you haven’t checked on the busiest domestic routes by seat capacity yet, it’s the right time. The article is shared within the United States of America. The airports would let you understand the domination over the list of the top busiest airports with routes serving Alaska and Hawaii.
Meanwhile, one more approach is there—the busiest air routes in the world. The popular method is for flights between two destinations. The rankings also include a rectified measure point, including number of seats, fleet size and more.
Five Busiest Domestic US Routes
In the list of the busiest domestic air routes in the USA, this often changes with time. The measuring aspects include monthly traffic and seasonal routes. The data revealed by OAG says the single busiest route in the US by seat numbers in July is New York LaGuardia to Chicago O’Hare. It ensures a total of 306,970 seats.
Followed by this second comes from New York only—it’s from New York JFK to Los Angeles, with almost the same number of seats. The total scheduling over the routes includes 306,621 within 349 seats, which is a bit fewer than the New York LaGuardia route. Thirdly, the busiest route is shorter than Las Vegas to Los Angeles, carrying 285,056 seats. The countability followed in fourth place is the route from Delta’s megahub in Atlanta to Orlando. It has 280,840 seats. The capturing is further proceeded with Los Angeles to Chicago O’Hare with 272,607 seats.
Next Busiest Domestic US Routes
Another of the busiest domestic US routes by seat number also serves major cities in the country. The accountability over the 6th is within two Californian metro cities, Los Angeles and San Francisco. The scheduling on seats is over 268,365 seats and is the busiest domestic intrastate route. The next way followed is from Los Angeles, but goes to Honolulu in Hawaii and will carry 259,642 seats. This is the busiest route outside of the 48 contiguous states.
Seattle-Tacoma International Airport is a prime port connecting Alaska to the rest of the US. The travel route is heavily scheduled and is served primarily by Alaska Airlines, followed by Delta. The total scheduling of seats is around 256,267.
Eventually, AA will be operational with six hubs, with Seattle as the primary hub and Anchorage as another important destination for flights across the state. Meanwhile, there is only one inter-island route on the list—Honolulu to Kahului with 255,267 seats.
The US Has Dispersed Airports & Destinations
The fact is that the US doesn’t have as many over-busy domestic routes as it does international domestic routes. The multiple airports in the US are serving as greater hubs like JFK, LaGuardia, Newark Liberty—serving greater New York City. But on the other side, LAX and Burbank serve Los Angeles.
US Carriers By Seat Numbers
Although the Chinese aviation market has grown in the past few years, the US remains the largest aviation hub in the world. Typically, the US has three major airlines as mainline fleets of around 1,000 aircraft—Delta Air Lines, American Airlines and United Airlines. The Southeast Airlines, however, has a Boeing 737 fleet of 800 aircraft.
Data shared by the OAG for June 2025 shows that American is a step ahead. It carried over a total of 23.2 million seats in June. Next is Delta with 20.8 million seats, Southwest with 20.5 million seats, and United with 17.8 million seats.
The next busiest airlines by seat numbers were Alaska at 5.4 million, JetBlue at 3.6 million, Spirit at 3.5 million, Frontier at 3.4 million, Allegiant at 2.4 million, and Hawaiian at 1.2 million seats. Alaska is in the process of integrating with Hawaiian, and that will solidify its position as one of the major airlines in the United States.
Top Ten Domestic Routes Across The World
Capturing the largest aviation market in the world—the US has led its name to the top within the top ten domestic air routes by seat numbers. Most of its routes are to Asia, including the Middle East and Australia. However, the busiest route is within South Korea from Seoul Gimpo. Next is in Japan from Tokyo Haneda to Sapporo, the northern Hokkaido Island, with 1.1 million seats.
It’s followed within Vietnam, including two major hubs of Hanoi and Ho Chi Minh City. Japan reappears on the list with 956,000 seats between Tokyo Haneda and Fukuoka. In fifth place are the two major Saudi Arabian cities of Jeddah and Riyadh, with 819,000 seats.
Let us round up the top ten domestic routes list: Australia’s Melbourne to Sydney route, Japan’s Tokyo Haneda to Okinawa route, Vietnam’s Da Nang to Hanoi route, India’s Mumbai to Delhi route, and China’s Shanghai Hongqiao to Shenzhen route. The Shanghai to Shenzhen route has 613,000 seats, meaning the busiest US route (LaGuardia to O’Hare) with its 307,000 seats is not even close to appearing on the top ten global list.
Constantly Changing Ranking
Although the ranks get changed with time, of course, dynamically. The major routes were down year-on-year. Alaska’s important connections with the Lower 48 were down. The route between Anchorage and Seattle dropped in capacity by 12%.
So far, United Airlines has concluded the most significant increase in seating capacity by 1.2 million seats for June 2025. Delta came second, adding 785,000 seats, and American followed, adding 640,900 seats. While still a small airline, the young airline Breeze Airways grew considerably, increasing its seating capacity by 225,000 seats, representing an increase in capacity by 44%.
