Flight Gimpo International Airport departs from Seoul Gimpo International Airport at 15:45 and arrives at Tokyo Haneda Airport at 17:50.
The flighttime is about 2h 05m. The distance travelled ("as the bird flies"): 1450 Km. So the average speed is roughly 696 Km.
The best day to arrive at Seoul is Saturday and it would be best to avoid Wednesday, as prices are on average 39.04% higher than on Saturday. (Average prices, based on 1083525 datapoints.)
We have a lot more statistics for flights NH 6970 and between Seoul and Tokyo.