Flight Hong Kong International Airport departs from Hong Kong Hong Kong International Airport at 08:20 and arrives at Siem Reap Siem Reap-Angkor International Airport at 10:05.
The flighttime is about 2h 45m. The distance travelled ("as the bird flies"): 1165 Km. So the average speed is roughly 424 Km.
There is an 1 hour time difference between Hong Kong and Siem Reap