Flight Hong Kong International Airport departs from Hong Kong Hong Kong International Airport at 15:45 and arrives at Siem Reap Siem Reap-Angkor International Airport at 17:50.
The flighttime is about 3h 05m. The distance travelled ("as the bird flies"): 1165 Km. So the average speed is roughly 378 Km.
There is an 1 hour time difference between Hong Kong and Siem Reap