
The world’s busiest air route is a domestic link that connects an island off the coast of Korea with the older, secondary airport in the capital, Seoul. Seven airlines compete on the trip. Fares are so low that even booking just 48 hours ahead for a Christmas Day flight reveals a price of just £14 for the 75-minute, 280-mile journey. OAG, the global aviation analyst, has revealed the clear winner in passenger numbers for 2025: Seoul Gimpo to Jeju Island.
The route is extremely popular with Korean holidaymakers, with almost 40,000 seats available each day.