Flight International Airport departs from Jeju City International Airport at 19:15 and arrives at Busan Gimhae International Airport at 20:15.
The flighttime is about 1h 00m. The distance travelled ("as the bird flies"): 296 Km. So the average speed is roughly 296 Km.
The best day to arrive at Jeju City is Saturday and it would be best to avoid Thursday, as prices are on average 96.17% higher than on Saturday. (Average prices, based on 154698 datapoints.)
We have a lot more statistics for flights KE 1554 and between Jeju City and Busan.