Flight Haneda Airport departs from Tokyo Haneda Airport at 14:30 and arrives at Osaka Kansai International Airport at 15:40.
The flighttime is about 1h 10m. The distance travelled ("as the bird flies"): 511 Km. So the average speed is roughly 438 Km.
The best day to arrive at Tokyo is Monday and it would be best to avoid Tuesday, as prices are on average 154.51% higher than on Monday. (Average prices, based on 6943279 datapoints.)
We have a lot more statistics for flights JL 121 and between Tokyo and Osaka.