Flight Haneda Airport departs from Tokyo Haneda Airport at 08:00 and arrives at Kagoshima Kagoshima Airport at 09:50.
The flighttime is about 1h 50m. The distance travelled ("as the bird flies"): 1048 Km. So the average speed is roughly 572 Km.
The best day to arrive at Tokyo is Monday and it would be best to avoid Tuesday, as prices are on average 366.68% higher than on Monday. (Average prices, based on 390997 datapoints.)
We have a lot more statistics for flights JL 643 and between Tokyo and Kagoshima.