Flight Don Mueang International Airport departs from Bangkok Don Mueang International Airport at 08:50 and arrives at Yangon Yangon International Airport at 09:40.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 499 Km. So the average speed is roughly 374 Km.
There is an 0.5 hour time difference between Bangkok and Yangon