Flight Incheon International Airport departs from Seoul Incheon International Airport at 06:35 and arrives at Manila Ninoy Aquino International Airport at 09:55.
The flighttime is about 4h 20m. The distance travelled ("as the bird flies"): 1530 Km. So the average speed is roughly 353 Km.
There is an 1 hour time difference between Seoul and Manila
