Flight Haneda Airport departs from Tokyo Haneda Airport at 09:05 and arrives at Kagoshima Kagoshima Airport at 10:55.
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 Friday and it would be best to avoid Thursday, as prices are on average 155.16% higher than on Friday. (Average prices, based on 390934 datapoints.)
We have a lot more statistics for flights NH 621 and between Tokyo and Kagoshima.