Flight Haneda Airport departs from Tokyo Haneda Airport at 11:05 and arrives at Fukuoka Fukuoka Airport at 13:05.
The flighttime is about 2h 00m. The distance travelled ("as the bird flies"): 1048 Km. So the average speed is roughly 524 Km.
The best day to arrive at Tokyo is Sunday and it would be best to avoid Wednesday, as prices are on average 199.1% higher than on Sunday. (Average prices, based on 3279867 datapoints.)
We have a lot more statistics for flights JL 315 and between Tokyo and Fukuoka.