North America's Busiest Domestic Flight Route Isn't In The US, According To 2025 Data

North America's most heavily traveled domestic air corridor may not be where you expect. For the second year in a row, the continent's busiest domestic flight route is not in the U.S. According to 2025 data from the Official Aviation Guide (OAG), the air corridor between Vancouver and Toronto has once again ranked as the continent's most heavily scheduled domestic route.

While Canada's population is only about 13% of the U.S.' 340 million, its busiest flight route still outpaces U.S. counterparts, edging out the trip between New York City and Los Angeles, which saw 3.43 million seats. By a relatively narrow margin, the Vancouver to Toronto route recorded 3.65 million scheduled seats to claim the top spot.

The continued dominance of Canada's transcontinental route reflects strong year-round demand connecting Canada's first- and third-largest cities. While Montreal is more populated than Vancouver, the 300-mile journey between Toronto and Montreal reduces demand for flights compared to the 2,800 miles between Toronto and Vancouver. Heavy business travel, tourism, and cross-country connectivity all contribute to its consistently high volume. Some Canadians have also recently chosen to avoid travel to the U.S., just one reason tourism in the U.S. is seeing a dramatic decline. This shift may also contribute to the higher demand for domestic routes, with more passengers heading to Toronto or Vancouver rather than south of the border.

Despite leading North America, Canada's impressive top ranking doesn't have the same impact internationally. In fact, the Vancouver-Toronto route doesn't even rank in the top 10 on the global stage. The highest-capacity domestic routes are concentrated in Asia, with nine of the top 10 busiest routes operating in the Asia Pacific region.

In 2025, the world's busiest domestic route was between Seoul and Jeju, South Korea. With a whopping 14.38 million scheduled seats, it makes Canada's winning 3.65 million seem pretty modest. Japan followed closely behind, with the routes between Tokyo and Sapporo or Fukuoka both exceeding 11 million scheduled seats. Interestingly, while Singapore's Changi and Qatar's Doha Hamad International are consistently ranked among the top five best-rated airports in the world, neither serviced any of the top 10 busiest routes.

Within North America, U.S. routes still dominate overall rankings, filling every other position in the top 10. Three routes departing from or arriving at Atlanta Hartsfield-Jackson International, the world's busiest airport, rank among the top 10 busiest U.S. domestic routes.