Paris for 31 percent of the GDP of France. According to the Economist Intelligence Unit Worldwide Cost of Living Survey in 2018, Paris was the second-most expensive city in the world, behind Singapore and ahead of Zurich, Hong Kong, Oslo and Geneva. The city is a major rail, highway, and air-transport hub served by two international airports: Paris-Charles de Gaulle (the second busiest airport in Europe after London Heathrow Airport with 69.5 million passengers in 2017) and Paris-Orly. Opened in 1900, the city's subway system, the Paris Métro, serves 5.23 million passengers daily, and is the second busiest metro system in
Transport in Paris A yet larger airport to the south of the Capital, Orly Airport, began welcoming flights from 1945, and yet another airport to the north of the City, Roissy-Charles-de-Gaulle, opened its gates from 1974. Today the former airfields of Issy-les-Moulineaux have become a Heliport annex of Paris, and Le Bourget an airfield reserved for smaller aircraft. Roissy-Charles-de-Gaulle takes the majority of international flights to and from Paris, and Orly is a host to mostly domestic and European airline companies. In addition, a few low-cost carrier airlines, notably Ryanair and Wizz Air, offer flights to Beauvais–Tillé Airport and Châlons Vatry Airport, while