Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 19:05 and arrives at Hanoi Noi Bai International Airport at 21:10.
The flighttime is about 2h 05m. The distance travelled ("as the bird flies"): 593 Km. So the average speed is roughly 285 Km.
The best day to arrive at Bangkok is Thursday and it would be best to avoid Tuesday, as prices are on average 49.24% higher than on Thursday. (Average prices, based on 920049 datapoints.)
We have a lot more statistics for flights VN 618 and between Bangkok and Hanoi.