Flight Incheon International Airport departs from Seoul Incheon International Airport at 19:05 and arrives at Osaka Kansai International Airport at 21:05.
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 Friday and it would be best to avoid Tuesday, as prices are on average 241.53% higher than on Friday. (Average prices, based on 1968115 datapoints.)
We have a lot more statistics for flights KE 721 and between Seoul and Osaka.