Flight Chiang Mai International Airport departs from Chiang Mai Chiang Mai International Airport at 16:20 and arrives at Kunming Wujiaba International Airport at 18:40.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 439 Km. So the average speed is roughly 329 Km.
There is an 1 hour time difference between Chiang Mai and Kunming