Flight Incheon International Airport departs from Seoul Incheon International Airport at 15:15 and arrives at Osaka Kansai International Airport at 17:15.
The flighttime is about 2h 00m. The distance travelled ("as the bird flies"): 1002 Km. So the average speed is roughly 501 Km.
The best day to arrive at Seoul is Saturday and it would be best to avoid Wednesday, as prices are on average 147.44% higher than on Saturday. (Average prices, based on 2256156 datapoints.)
We have a lot more statistics for flights KE 725 and between Seoul and Osaka.