The Kathmandu airport has a single runway of 10,007 feet (3,050 m). Around three kilometres needed to host the world's largest passenger jets, such as the Airbus A380, which needs about 9000 feet (2743 metres) to take off and 5000 feet (1524 metres) to land. An average (smaller) commercial aircraft - such as an A320 or Boeing 737 - requires smaller distances.
So airport in nepal is not so short for even haviest planes.
For reference, London Heath's two runways are 12,802 and 12,001 feet (3902 and 3658 metres) and both regularly welcome the likes of the Airbus A380 and Boeing 777. London Gatwick has a 10,879-foot (3316-metre) runway while Manchester's is 10,000 feet (3048 metre).