Flight Suvarnabhumi Airport departs from Bangkok Suvarnabhumi Airport at 10:35 and arrives at Dhaka Shahjalal International Airport at 12:10.
The flighttime is about 2h 35m. The distance travelled ("as the bird flies"): 1152 Km. So the average speed is roughly 446 Km.
There is an 1 hour time difference between Bangkok and Dhaka