Flight Gimpo International Airport departs from Seoul Gimpo International Airport at 08:45 and arrives at Jeju City International Airport at 09:55.
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 Tuesday, as prices are on average 1660.22% higher than on Monday. (Average prices, based on 606214 datapoints.)
We have a lot more statistics for flights OZ 8915 and between Seoul and Jeju City.