Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 09:35 and arrives at Yangon Yangon International Airport at 10:35.
The flighttime is about 1h 30m. The distance travelled ("as the bird flies"): 516 Km. So the average speed is roughly 344 Km.
There is an 0.5 hour time difference between Bangkok and Yangon