Flight Tribhuvan International Airport departs from Kathmandu Tribhuvan International Airport at 22:40 and arrives at Doha International Airport at 01:30.
The flighttime is about 5h 50m. The distance travelled ("as the bird flies"): 3758 Km. So the average speed is roughly 644 Km.
There is an 3 hour time difference between Kathmandu and Doha