Tan Son Nhat International Airport has its origins in the early 1920s when the French colonial government constructed a small airport with unpaved runways, known as Tân S?n Nh?t Airfield near the village of Tan Son Nhut, and was later expanded in 1930s. By mid-1956, with U.S. aid, a 7,200-foot (2,190 m) runway had been built; the airfield near Saigon became known as South Vietnam's principal international gateway. During the Vietnam War (or Second Indochina War), Tan Son Nhut Air Base (then using the Southern spelling "Tân S?n Nh?t") was an important facility for both the U.S. Air Force and the Republic of Vietnam Air Force. Between 1968 and 1974, Tan Son Nhut Airport was one of the busiest military airbases in the world. Pan Am schedules from 1973 show that during the last days of South Vietnam, Boeing 747 service was being operated four times a week to San Francisco via Guam and Manila. Continental Airlines operated up to 30 Boeing 707 military charters per week to and from Tan Son Nhut Airport during the 1968–74 period. On 9 December 2004, United Airlines became the first U.S. airline to fly to Vietnam since Pan Am's last flight during the Fall of Saigon in April 1975. Flight UA 869, operated using a Boeing 747-400 landed at Ho Chi Minh City, the terminus of the flight that originated from San Francisco via Hong Kong. On 29 October 2006, this service was switched from San Francisco to Los Angeles with a stop in Hong Kong, operating as UA 867 (also using a 747–400). In 2009, the service UA 869 has resumed once again from San Francisco via Hong Kong International Airport. In 2006, Tan Son Nhat International Airport served approximately 8.5 million passengers (compared with 7 million in 2005) with 64,000 aircraft movements. It has recently accounted for nearly two-thirds of the arrivals and departures at Vietnam's international gateway airports. Due to increasing demand (about 15–20% per annum), the airport has been continuously expanded by the Southern Airports Corporation. In 2010, Tan Son Nhat domestic terminal handled 8 million passengers, its maximum capacity. The airport reached its full capacity of 20 million passengers in 2013, two years earlier than predicted. Both domestic and international terminal are being expanded to meet the increasing demand. In December 2014, expansion for the domestic terminal was finished, boosting the terminal's capacity to 13 million passengers per annum. In September 2017, People's Army of Vietnam ceded 21 hectare of military land in the vicinity of the airport to Airports Corporation of Vietnam for civil use. This gave way for the construction of 21 new aircraft parking spaces, expected to be completed by Tet holidays in 2018. Tan Son Nhat will then have 72 parking spaces for airplanes. Of the routes the airport serves, the Ho Chi Minh City–Hanoi route is the busiest in Southeast Asia and the seventh busiest in the world, serving 6,769,823 customers in 2017. In October 2022, the aircraft revetments built by the U.S. were removed to make way for a taxiway. Seven larger ones are set to be constructed as replacement 800 meters away.