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South Korea’s Jeju (CJU) - Seoul Gimpo (GMP) is the World’s Busiest Airline Route in 2025, Latest OAG Data Reveals

Written by OAG | Dec 22, 2025 10:36:30 AM

An average of 39,000 seats per day operate on the world’s top route. 

Key findings:

  • 14.4 million seats were scheduled between Jeju (CJU)-Seoul Gimpo (GMP) in 2025.
  • Asia Pacific dominates, accounting for 9/10 of the top routes globally.
  • Hong Kong (HKG) – Taipei (TPE) continues to be the busiest cross-border route.  
  • Jeddah (JED) – Riyadh (RUH) is the fastest growing top ten route YoY: +13% seats vs 2024.

LONDON – December 22, 2025 – OAG, the leading data platform for the global travel industry, today revealed its ranking of 2025’s Busiest Airline Routes. The analysis is powered by  OAG's Global Airline Schedules Data and provides an overview of global route performance and trends.

Jeju to Seoul Gimpo is the busiest airline route of 2025 with 14.4 million seats scheduled, a modest 1% increase versus 2024. There is room yet for growth on this route, which is still 17% short of regaining its capacity level of 2019. Seven carriers operate on this intensely competitive route. 

The second and third placed routes are both in Japan: Sapporo New Chitose (CTS) – Tokyo Haneda (HND) and Fukuoka (FUK) – Tokyo Haneda (HND) with 12.1M and 11.5M seats respectively.

The top 10 comprises entirely of domestic flights, and Asia Pacific dominates with 9 out of 10 being in the region. The one route outside of Asia Pacific is fifth placed Jeddah (JED) – Riyadh (RUH), which has seen the fastest growth of any top ten route. 9.8M seats on JED-RUH represent annual growth of 13%. Fourth placed Hanoi (HAN) to Ho Chi Minh (SGN) also grew by 4% YoY and tenth placed Shanghai (SHA) – Shenzhen (SZX) has seen capacity increase by 5% to move into the top ten from its eleventh spot last year. 

Focusing on cross-border flights, Hong Kong (HKG) – Taipei (TPE) is the busiest route of 2025 with 6.8M seats followed by Cairo (CAI) – Jeddah (JED) with 5.8M seats and Kuala Lumpur (KUL) – Singapore Changi (SIN) with 5.6M.