For aviation enthusiasts, travel lovers, and those fascinated by Korean culture, here's a remarkable fact: South Korea, despite its relatively small size, is home to the world's busiest domestic air route. In December 2025, the Jeju International Airport (CJU) to Seoul Gimpo Airport (GMP) route claimed the top spot in OAG's ranking of the world's busiest domestic routes with an astonishing 1.46 million seats, while also showing the fastest growth among the top ten busiest routes.
The Korean Aviation Market: A Fierce Competitive Landscape
Imagine a bustling marketplace with vendors competing vigorously for customers. The Korean aviation market operates with similar intensity, where low-cost carriers (LCCs) play a crucial role as affordable, popular options for travelers.
In November 2025, South Korea's total aviation capacity reached an impressive 14.5 million seats, with international routes accounting for 62% and domestic routes making up the remaining 38%. This distribution highlights the country's active international connections.
However, beneath the surface of apparent competition, one aviation group has quietly established dominance. Following the December 2024 merger of Korean Air and Asiana Airlines - the nation's two aviation giants - the newly formed Korean Air Group, along with its LCC subsidiaries Jin Air and Air Busan, now commands 77% of the domestic market capacity. This consolidation has created what amounts to an oligopoly in South Korea's domestic aviation sector.
The "Super Route": Jeju-Seoul Gimpo's Unrivaled Dominance
If Korean Air Group dominates the domestic market, the CJU-GMP route stands as the undisputed superstar of domestic air travel. This route's November 2025 performance metrics were extraordinary:
- Seven airlines operating the route
- 209 daily round-trip flights
- 1.4 million seats offered
- Asiana Airlines operating 57 round-trips, Korean Air 55, and Jeju Air 41
Several factors contribute to this route's exceptional popularity:
- Jeju Island's status as a premier tourist destination with stunning natural scenery and unique cultural attractions
- Air travel being the only practical option to reach the island
- An average one-way economy fare of just $33, thanks to intense LCC competition
Global Reach: South Korea's International Aviation Network
South Korea's international aviation sector showed strong recovery in November 2025, with 9 million seats offered - a 4.7% increase over 2019 levels. Eighty-four airlines compete in this space, with Korean carriers holding 68% of the international capacity.
The international market reveals distinct regional trends:
Japan: The Leading International Market
With 2.61 million seats in November 2025 (an 89% increase over 2019), Japan stands as South Korea's largest international aviation market. The Seoul Incheon-Tokyo Narita and Seoul Incheon-Osaka Kansai routes rank among the world's ten busiest international routes. Several factors drive this growth:
- Geographic proximity enabling short flight times
- Strong cultural exchange between the nations
- Robust economic connections
- LCC competition keeping fares competitive
China: Slow Post-Pandemic Recovery
While China remains South Korea's second-largest international market with 1.57 million seats, this figure remains below 2019 levels due to:
- Strict pandemic control measures
- Weakened outbound tourism demand
- Geopolitical tensions
Singapore: Where Business Meets K-Culture
Capacity to Singapore grew 44% over 2019 levels, fueled by:
- Strong business connections
- Premium travel opportunities
- Growing interest in Korean culture (from cuisine to K-pop)
United States: Diaspora and Business Links
The U.S. market grew 21% over 2019, supported by:
- A large Korean-American population
- Strong commercial ties
- The Korean Air-Delta joint venture strengthening Incheon's position as a transpacific hub
The Formula for South Korea's Aviation Success
South Korea's aviation boom results from multiple converging factors:
- Strong domestic tourism demand, particularly to Jeju Island
- LCCs making air travel more accessible
- Proactive international engagement policies
- Powerful airline groups with global competitiveness
- The worldwide popularity of Korean culture
The combination of full-service carriers' scale advantages and LCCs' flexibility continues to drive growth in both domestic and international markets, establishing South Korea as one of Asia's most dynamic aviation markets.
Future Prospects: Challenges and Opportunities
While South Korea's aviation sector shows remarkable strength, it faces several challenges:
- Intensifying market competition
- Geopolitical risks in the region
- Ongoing pandemic-related uncertainties
However, significant opportunities exist:
- Global economic recovery boosting travel demand
- Potential improvement in China-South Korea relations
- Emerging market growth creating new possibilities
With these factors in play, South Korea's aviation sector appears poised to maintain its strong growth trajectory in the coming years.