The Incheon International Airport is crowded with air travellers, Jan. 26. Yonhap

One in four flights operated by Korean airlines last year experienced delays in flight departures or arrivals, government data showed Monday.

According to the transport ministry data submitted to the office of Rep. Ahn Tae-jun of the main opposition Democratic Party of Korea, the average delay rate for domestic and international flights operated by 10 domestic airlines in 2024 stood at 25.7 percent.

According to ministry guidelines, a flight is considered delayed if it arrives or departs more than 15 minutes past its scheduled time. Of the 678,489 flights operated by Korean airlines last year, 174,078 were recorded as delayed.

The ministry attributed last year's high delay rate to increased international flights leading to greater airport congestion, as well as frequent turbulence and airspace restrictions on international flight paths.

Among international routes, Air Seoul had the highest delay rate of 46.6 percent, followed by Eastar Jet with 38 percent and Jin Air with 35.4 percent. For domestic routes, T'way Air had the highest delay rate of 31.3 percent, followed by Air Seoul. (Yonhap)