The airport is considered as a starting point for Mount Everest international tourists, with several daily flights to Lukla.

[6] The formal beginning of aviation in Nepal is generally placed at Gauchaur in 1949 with the landing of a Beechcraft Bonanza carrying the Indian ambassador, although there are disputed claims that Simara Airport existed in some form as early as 1946.

[11] On 20 February 1950, an Indian registered Dakota DC-3 commenced the first ever scheduled service, linking Kathmandu to Patna, Kolkata and Delhi.

On 10 November 1950, two Indian planes landed at Gauchaur Airport and carried the young king along with his grandfather to Delhi.

After the Delhi Accord, the Rana regime ended and King Tribhuvan landed at Gauchaur Airport as the monarch on 18 February 1951, bringing a return of democracy in Nepal.

[12] In 1961, Queen Elizabeth II landed in a Dakota plane for her first visit to Nepal, one of the most high-profile arrivals at the airport.

[14] In 1989, the construction of the terminal building was completed and on 18 February 1990, the newly built TIA complex was officially inaugurated by King Birendra Bir Bikram Shah.

[12] In 1992, Necon Air, Nepal's first private airline commenced domestic operations from TIA with a Hawker Siddeley HS 748.

Likewise, Amplitude modulation signalling system (AMSS) and a very-small-aperture terminal (V-SAT) were also installed at the airport.

[12][15] In May 2007, Austrian Airlines discontinued its flight to Vienna, Nepal's last direct air link to Europe.

[16] In September 2013, Turkish Airlines launched direct flights from Istanbul to Kathmandu, re-establishing Nepal's connection with continental Europe.

There is also a bay at the eastern side of the airport that can hold two wide-body and two ATR 72 or similar type of aircraft.

[24] There are two non-precision approaches available at the Kathmandu Airport; VHF omnidirectional range along a distance measuring equipment (VOR/DME) and Required Area Navigation (RNAV/RNP).

[26] Due to mountainous terrain, VOR/DME systems are installed at Kathmandu and Bhattedanda, along the extended approach path of runway 02 for better reception by aircraft.

[27] High intensity 870 m (2,854 ft 4 in) extended centerline lights are installed at the southern end of the airport to assist with the approach.

[30] Radisson Hotel Kathmandu operates an executive lounge for first and business class passengers of several airlines[31] and Thai Airways operates a Royal Thai Silk lounge for its business-class passengers, as well as Star Alliance Gold card holders.

[35] Buddha Air operates a closed door hangar facility, which can accommodate narrow-body aircraft at the eastern side of the airport.

[citation needed] According to the CAAN Aviation Report – 2017,[142] Tribhuvan International will undergo expansions under Transport Project Preparatory Facility funded partly by the Asian Development Bank.