Flight Haneda Airport departs from Tokyo Haneda Airport at 07:20 and arrives at Kagoshima Kagoshima Airport at 09:25.
The flighttime is about 2h 05m. The distance travelled ("as the bird flies"): 1048 Km. So the average speed is roughly 503 Km.
The best day to arrive at Tokyo is Wednesday and it would be best to avoid Monday, as prices are on average 78.04% higher than on Wednesday. (Average prices, based on 391193 datapoints.)
We have a lot more statistics for flights BC 301 and between Tokyo and Kagoshima.