Flight International Airport departs from Osaka International Airport at 17:00 and arrives at Tokyo Haneda Airport at 18:20.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 485 Km. So the average speed is roughly 364 Km.
The best day to arrive at Osaka is Saturday and it would be best to avoid Monday, as prices are on average 37.98% higher than on Saturday. (Average prices, based on 1870267 datapoints.)
We have a lot more statistics for flights JL 128 and between Osaka and Tokyo.