Flight International Airport departs from Osaka International Airport at 20:15 and arrives at Tokyo Haneda Airport at 21:25.
The flighttime is about 1h 10m. The distance travelled ("as the bird flies"): 485 Km. So the average speed is roughly 416 Km.
The best day to arrive at Osaka is Saturday and it would be best to avoid Sunday, as prices are on average 52.22% higher than on Saturday. (Average prices, based on 2209891 datapoints.)
We have a lot more statistics for flights JL 138 and between Osaka and Tokyo.