Flight Incheon International Airport departs from Seoul Incheon International Airport at 12:15 and arrives at Fukuoka Fukuoka Airport at 13:40.
The flighttime is about 1h 25m. The distance travelled ("as the bird flies"): 518 Km. So the average speed is roughly 366 Km.
The best day to arrive at Seoul is Tuesday and it would be best to avoid Saturday, as prices are on average 382.02% higher than on Tuesday. (Average prices, based on 742091 datapoints.)
We have a lot more statistics for flights LJ 263 and between Seoul and Fukuoka.