A tram network has long been planned in Skopje and the idea was first proposed in the 1980s. The project became real in 2006 when the mayor Trifun Kostovski asked for feasibility studies. His successor Koce Trajanovski launched a call for tenders in 2010 and the first line is scheduled for 2019. A new network for small buses started to operate in June 2014, not to replace but to decrease the number of big buses in the city centre. Airport The airport was built in 1928. The first commercial flights in Skopje were introduced in 1929 when the Yugoslav carrier Aeroput introduced a route linking the city with the capital, Belgrade. A year later the route was extended to Thessaloniki in Greece, and further extended to Greek capital Athens in 1933. In 1935 Aeroput linked Skopje with Bitola and Niš, and also operated a longer international route linking Vienna and Thessaloniki through Zagreb, Belgrade and Skopje. After the Second World War, Aeroput was replaced by JAT Yugoslav Airlines, which linked Skopje to a number of domestic and international destinations until the dissolution of Yugoslavia in the early 1990s. Nowadays, International Airport Skopje is in Petrovec, some east of the city. Since 2008, it has been managed by the Turkish TAV Airports Holding and it can accommodate up to four million passengers per year. The annual traffic has constantly risen since 2008, reaching one million passengers in 2014. Skopje's airport has connections to several European cities, including Athens, Vienna, Bratislava, Zürich, Brussels, Istanbul, London and Rome. It also maintains a direct connection with Dubai and Doha, Qatar. Culture Cultural institutions Skopje is home to the largest cultural institutions of the country, such as the National and University Library "St. Kliment of Ohrid", the Macedonian Academy of Sciences and Arts, the National Theatre, the National Philharmonic Orchestra and the Macedonian Opera and Ballet. Among the local institutions are the Brothers Miladinov Library which has more than a million documents, the Cultural Information Centre which manages festivals, exhibitions and concerts, and the House of Culture Kočo Racin which is dedicated to contemporary art and young talents. Skopje has also several foreign cultural centres, such as a Goethe-Institut, a British Council, an Alliance française, an American Corner. The city has several theatres and concert halls. The Univerzalna Sala, seating 1,570, was built in 1966 and is used for concerts, fashion shows and congresses. The