Flight Phnom Penh International Airport departs from Phnom Penh Phnom Penh International Airport at 20:00 and arrives at Yangon Yangon International Airport at 21:30.
The flighttime is about 2h 00m. The distance travelled ("as the bird flies"): 973 Km. So the average speed is roughly 486 Km.
There is an 0.5 hour time difference between Phnom Penh and Yangon