Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 08:25 and arrives at Osaka Kansai International Airport at 15:55.
The flighttime is about 5h 30m. The distance travelled ("as the bird flies"): 3931 Km. So the average speed is roughly 715 Km.
There is an 2 hour time difference between Bangkok and Osaka