Flight Incheon International Airport departs from Seoul Incheon International Airport at 11:00 and arrives at Macau Macau International Airport at 13:50.
The flighttime is about 3h 50m. The distance travelled ("as the bird flies"): 1654 Km. So the average speed is roughly 431 Km.
There is an 1 hour time difference between Seoul and Macau