Zurich Airport is the largest international airport of Switzerland and the principal hub of Swiss International Air Lines. It serves Zurich, the largest city in Switzerland, and, with its surface transport links, much of the rest of the country. The airport is located nine kilometres north of central Zurich, in the municipalities of Kloten, Rümlang, Oberglatt, Winkel, and Opfikon, all of which are within the canton of Zurich.