Flight Incheon International Airport departs from Seoul Incheon International Airport at 15:00 and arrives at Osaka Kansai International Airport at 16:40.
The flighttime is about 1h 40m. The distance travelled ("as the bird flies"): 1002 Km. So the average speed is roughly 601 Km.
The best day to arrive at Seoul is Wednesday and it would be best to avoid Saturday, as prices are on average 255.78% higher than on Wednesday. (Average prices, based on 1969369 datapoints.)
We have a lot more statistics for flights LJ 239 and between Seoul and Osaka.