Flight Narita International Airport departs from Tokyo Narita International Airport at 21:40 and arrives at Hong Kong Hong Kong International Airport at 01:40.
The flighttime is about 5h 00m. The distance travelled ("as the bird flies"): 3064 Km. So the average speed is roughly 613 Km.
There is an 1 hour time difference between Tokyo and Hong Kong
The best day to arrive at Tokyo is Thursday and it would be best to avoid Friday, as prices are on average 154.1% higher than on Thursday. (Average prices, based on 16012381 datapoints.)
We have a lot more statistics for flights CX 501 and between Tokyo and Hong Kong.