If you stay in the Kathmandu and have no time to go to one of the numerous treks in the Everest region, an hot air balloon flight is probably the most exciting way to see the surrondings himalayan peaks .
Since 1996, Balloon sunrise Nepal organizes commercial flights in the Kathmandhu valley. This company was founded by Chris Dewhrist, an australian who became in 91 the first person to pilot a ballon over Mount Everest. The film of this flight was screened worlwide. (The landing was "very rough").
Today, you won't go so far !
Duration of the flight (between 60 and 90 minutes) and the altitude reached (betweeen 8 and 10 000 feet) will depend on weather conditions.
If winds are quite hard, the flight will be shorter, as the pilot won't leave the valley in order to be sure to find a safe landing place.
The balloon is decorated with "the all seeing eye of Buddha". Inside the large wicker basket, 9 passengers take place, together with the pilot and 6 big butane cylinders (more than twice than what is really needed, in case of....).