built originally on a deep layer of clay and swampy topsoil, would require considerable investment if they were to bear the weight of the new big airliners. The problem was particularly acute with Helsinki slated to host the 1952 Summer Olympics. Cost estimates showed that extending the runways, adding pilework under them and strengthening them in other ways would be prohibitively expensive, and the plans were abandoned. A new airfield built to international standards was first opened to traffic in 1952 in Vantaa, in time for the Olympics, today known as Helsinki Airport. Scheduled traffic gradually moved from Malmi to the new airport. Malmi Airport continued to serve a new category of commercial aviation, charter flights, for many years. In special circumstances, it also acted as a backup airfield for Helsinki Airport for lighter passenger aircraft. After the opening of Helsinki-Vantaa Airport, Malmi Airport was used mainly for general aviation. Professional flying education and professional aviation, as well as private aviation and aviation clubs, operated there. 75 to 80 percent of all flights were training flights, and in 2002, 50 percent of all pilots in Finland and two out of three professional pilots were trained there. From the point of view of air traffic, Malmi Airport is the only free-schedule international airfield for lighter traffic within 150 km of the capital (Helsinki Airport is the only coordinated airport in Finland, i.e., it does not serve non-scheduled traffic without a runway slot application that must be filed hours in advance). In 2013, about 7,500 landings of flights between Malmi and other airfields were logged just among Malmi's own flight operators, making Malmi the second-busiest airport for cross-country flights in Finland. The aviation shows and other public events at the airport have typically been enjoyed by tens of thousands of spectators. The Finnish Border Guard had its air base at the airport until the end of 2016, when the State moved all its operations elsewhere (about 14% of Malmi's operations), anticipating the airport's closure. Closure The closure of the airport was debated since about 2000, as the city of Helsinki needed the area for building housing for its growing population. On 25 March 2014, the Finnish government made a framework decision in principle to close down Malmi Airport and hand it over to residential use by the early 2020s. A prerequisite written into the government's decision was that the Border Guard and