Flight Bandaranaike International Airport departs from Colombo Bandaranaike International Airport at 00:25 and arrives at Kathmandu Tribhuvan International Airport at 16:05.The flight has a short stop at Kuala Lumpur.
The flighttime is about 15h 10m. The distance travelled ("as the bird flies"): 667 Km. So the average speed is roughly 44 Km.
There is an 0.5 hour time difference between Colombo and Kathmandu