Flight Incheon International Airport departs from Seoul Incheon International Airport at 21:05 and arrives at Honolulu International Airport at 10:35.
The flighttime is about 8h 30m. The distance travelled ("as the bird flies"): 8551 Km. So the average speed is roughly 1006 Km.
There is an 19 hour time difference between Seoul and Honolulu