Flight Gimpo International Airport departs from Seoul Gimpo International Airport at 17:20 and arrives at Jeju City International Airport at 18:30.
The flighttime is about 1h 10m. The distance travelled ("as the bird flies"): 271 Km. So the average speed is roughly 232 Km.
The best day to arrive at Seoul is Monday and it would be best to avoid Sunday, as prices are on average 212.99% higher than on Monday. (Average prices, based on 604686 datapoints.)
We have a lot more statistics for flights KE 1179 and between Seoul and Jeju City.
