Flight Incheon International Airport departs from Seoul Incheon International Airport at 16:35 and arrives at Yangon Yangon International Airport at 19:50.
The flighttime is about 5h 45m. The distance travelled ("as the bird flies"): 3421 Km. So the average speed is roughly 595 Km.
There is an 2.5 hour time difference between Seoul and Yangon