Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 15:55 and arrives at Hanoi Noi Bai International Airport at 18:05.
The flighttime is about 2h 10m. The distance travelled ("as the bird flies"): 593 Km. So the average speed is roughly 274 Km.
The best day to arrive at Bangkok is Sunday and it would be best to avoid Monday, as prices are on average 489.96% higher than on Sunday. (Average prices, based on 923556 datapoints.)
We have a lot more statistics for flights KQ 5300 and between Bangkok and Hanoi.