Flight Yangon International Airport departs from Yangon Yangon International Airport at 18:25 and arrives at Chiang Mai Chiang Mai International Airport at 20:15.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 315 Km. So the average speed is roughly 236 Km.
There is an 0.5 hour time difference between Yangon and Chiang Mai