One can reach Kathmandu by directly flying into the Tribhuvan International Airport of Kathmandu Valley.
Kathmandu can also be reached from border towns and other parts of the country by buses or by drive to Kathmandu.
Why Valley looks extraordinary
From Varanasi and Gorakhpur there is direct bus service to Kathmandu. To reach Kathmandu one can also hire private cabs. From Delhi/Varanasi and many big cities of India even special flights are there. Best way to reach Kathmandu is by air.