In 1940, the Imperial Japanese Army built Sendai Airport in order to use it for the Kumagaya Army Flight School, Masda Branch School Trainee Training Center. It was called by several names: Natory Airfield, Masda Airfield, and Yatory Airfield. In 1943, the Miho Army Flight Center moved into Sendai Airport and facilities were expanded and later reformed into the Sendai Army Flight School. At the end of World War II, the United States Army took control of the airport and its operations. In 1956, it was returned to Japan and transferred to the Ministry of Defense. The Ministry of Transport was designated to administer and use it. In 1957, the runway was extended to 1,200 metres (3,937 ft) and Nippon Helicopter Transport (now All Nippon Airways) established a route from Tokyo's (Haneda Airport) to Sendai. When the airport began to service commercial jets on 14 February 1970, runway 09/27 was extended to 2,000 metres (6,562 ft). Also, the flight school of Japan Ground Self Defense Force moved into North Utsunomiya Army Post. Beginning 6 April 1990, Asiana Airlines established a route from Seoul (Gimpo International Airport) to Sendai, thus beginning international service from the airport. Air China began scheduled service to Beijing via Dalian in 1994, which was followed by services to Shanghai and Changchun. In 1992, Runway 09/27 was extended further to 2,500 metres (8,202 ft) and 5 years later, in 1997, a new terminal was opened and the runway was extended further to 3,000 metres (9,843 ft). Due to the 1997 Asian Financial Crisis, Singapore Airlines suspended services in Sendai. The Sendai Airport Line rail link was completed on 18 March 2007 and began service between Sendai and Sendai Airport Station. The "Smile Terrace" observation deck opened on 19 March 2010. On 11 March 2011, the airport was damaged by the 2011 T?hoku earthquake and then substantially flooded by the subsequent tsunami. In addition to submerging the apron, taxiways and runway, the floodwaters reached up to parts of the 2nd level of the passenger terminal, rendering electrical equipment, transformers and safety equipment inoperable. Operations at Sendai as well as Odate-Noshiro Airport and Sado Airport, which had been controlled by Sendai Airport control tower, were suspended. Some 1,300 people were stranded within the terminal until 13 March 2011, when they were evacuated. By 17 March 2011, military engineers partially opened the airport for tsunami response flights. To reopen the airport, on 16 March 2011, a U.S. Air Force MC-130P Combat Shadow from the 17th Special Operations Squadron infiltrated a team from the 320th Special Tactics Squadron from Kadena Air Base into Matsushima, Miyagi, then moved overland to the airport. With assistance from Japan Self-Defense Forces, enough debris was removed in a few days to allow an MC-130H Combat Talon II aircraft to begin landing with more equipment, personnel, and supplies. After further cleanup with help from additional US and Japanese military units, on 20 March 2011, a US Air Force C-17 landed at the airport with 40 metric tons of relief supplies. Thereafter, the airport served as a transit location for airlifted supplies, totaling approximately 2 million tons of such items as blankets, water, and food. The US military set up and operated air traffic control operations for the airport until shortly before commercial traffic resumed, at which point air traffic control responsibility was resumed by Japanese controllers. The airport reopened to limited commercial traffic on 13 April 2011. Japan Airlines and ANA conducted a total of six flights a day to Tokyo Haneda Airport upon resumption of services, with Japan Airlines also offering limited flights to Osaka Itami airport. Due to damage caused by the earthquake and tsunami, all scheduled service (except for humanitarian flights) were suspended from 11 March 2011 until 13 April 2011.