Flight Incheon International Airport departs from Seoul Incheon International Airport at 10:10 and arrives at Fukuoka Fukuoka Airport at 11:35.
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 426.12% higher than on Tuesday. (Average prices, based on 730129 datapoints.)
We have a lot more statistics for flights TW 291 and between Seoul and Fukuoka.