Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 21:15 and arrives at Kunming Wujiaba International Airport at 00:45.
The flighttime is about 2h 30m. The distance travelled ("as the bird flies"): 337 Km. So the average speed is roughly 135 Km.
There is an 1 hour time difference between Bangkok and Kunming