Flight Indira Gandhi International Airport departs from Delhi Indira Gandhi International Airport at 16:20 and arrives at Kathmandu Tribhuvan International Airport at 18:10.
The flighttime is about 1h 20m. The distance travelled ("as the bird flies"): 917 Km. So the average speed is roughly 688 Km.
There is an 0.5 hour time difference between Delhi and Kathmandu