Flight Guangzhou Baiyun International Airport departs from Guangzhou Guangzhou Baiyun International Airport at 00:05 and arrives at Bangkok Don Mueang International Airport at 02:05.
The flighttime is about 3h 00m. The distance travelled ("as the bird flies"): 1440 Km. So the average speed is roughly 480 Km.
There is an 1 hour time difference between Guangzhou and Bangkok