Ubon Ratchathani Airport (IATA: UBP, ICAO: VTUU) is an airport in the capital district of Ubon Ratchathani, in Ubon Ratchathani Province, Northeastern Thailand. It currently serves as both a commercial airport and as a Royal Thai Air Force base. The airport was first opened in 1921, when the nearby Warin Chamrap district was affected by smallpox and cholera epidemic.[citation needed] The authorities have sent doctors and medical supplies by plane to Ubon Ratchathani province to alleviate the suffering of the residents. In 1955 it became Ubon Royal Thai Air Force Base for the Vietnam War; in 1975 the facility became[when?] an international civilian airport, with direct flights to Vietnam.[citation needed] These flights proved unprofitable, and while the international signage is still in place, only domestic flights have operated for a number of years.