Sliač Airport (IATA: SLD, ICAO: LZSL) or, historically, Letisko Tri Duby (literally, "The Three Oaks Airport") is an international airport in central Slovakia situated between the towns of Zvolen and Banská Bystrica and near the spa town of Sliač. The airport has one runway which is 2,400 m long (18/ 36). The airport is used by the military as well as commercially for civilian flights.
The "Tri Duby Airport" played an important role during the Slovak National Uprising in 1944 when it became the most important airport of the Anti-Nazi Resistance in Slovakia. Between September 6 and October 25, 1944, the airport was being used as the main base of the Slovak Insurgent Air Force but because of the advancing German units, it later had to be evacuated. While the territory controlled by the Slovak rebels was being encircled by the hostile German forces, "Tri Duby" and the nearby Zolná airport were the main gateways to the rest of the world. In addition to the significant Soviet aid to Slovakia, the United States, too, were sending in supplies and OSS operatives through "Tri Duby", and these flights were also used to evacuate American aeronauts liberated from the German POW camps.
The airport changed its name from "Tri Duby" to Sliač in 1945. In 2009, it was closed for a major reconstruction project financed in part by NATO and the EU. It was reopened for military use in May 2011, and for civilian use in June 2011. Sliač Airport currently operates charter flights to popular sea resort destinations Bourgas in Bulgaria and Antalya in Turkey. More commercial civilian flights are being planned on.