Daily trains also link Skopje with other North Macedonian towns, such as Kumanovo, Kičevo, Štip, Bitola or Veles. Skopje has several minor railway stations but the city does not have its own railway network and they are only serviced by intercity or international lines. On the railway linking the main station to Belgrade and Thessaloniki are Dračevo and Dolno Lisiče stations, and on the railway to Kičevo are Skopje-North, Gjorče Petrov and Saraj stations. Several other stations are freight-only. Skopje coach station opened in 2005 and is built right under the main railway station. It can host 450 coaches in a day. Coach connections to and from Skopje are much more efficient and diverse than train connections. Indeed, it is regularly linked to many North Macedonian localities and foreign cities including Istanbul, Sofia, Prague, Hamburg and Stockholm. Skopje has a bus network managed by the city and operated by three companies. The oldest and largest is JSP Skopje, a public company founded in 1948. JSP lost its monopoly on public transport in 1990 and two new companies, Sloboda Prevoz and Mak Ekspres, obtained several lines. However, most of the network is still in the hands of JSP which operates 67 lines out of 80. Only 24 lines are urban, the others serving localities around the city. Many of the JSP vehicles are red double-decker buses built by Chinese bus manufacturer Yutong and designed to resemble the classic British AEC Routemaster. 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. 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.