powers of World War II. These three air routes existed from February 1946 until German reunification in October 1990. They linked the exclave of West Berlin with West Germany and passed over the territory of communist East Germany. The airspace they encompassed was jointly administered from the Berlin Air Safety Center in West Berlin by representatives of the governments of all four victorious powers that had defeated Germany in World War II. The massive post-war reconstruction effort in West Berlin, the city's rapid economic recovery following the end of the Berlin Blockade and the beginning of the German economic miracle resulted in rapidly rising living standards and disposable incomes of the local population. Together with the lifting of travel restrictions imposed by other countries on West German passport holders in the immediate aftermath of World War II and West Berlin's location inside East Germany this in turn drove the local population's rapidly rising demand for overseas travel and the growing popularity of package tours involving air travel. As West Berlin was out of bounds for German airlines, local tour operators chartered aircraft of the British independent airlines and US supplemental carriers that began flying from the city's Tempelhof and Tegel airports in the early 1960s. Prior to Modern Air's arrival in Berlin, the biggest among these was US supplemental Saturn Airways. Saturn opened a base at West Berlin's Tempelhof Airport in 1964. Its Berlin-based fleet comprised Douglas DC-6 and DC-7 piston airliners, which were chartered by Flug-Union Berlin for its flying programme to several airports serving popular holiday resorts, chiefly in the Mediterranean. Flug-Union Berlin was the first tour operator with a West Berlin flying programme and acted at the time as the city's consolidator for the big West German tour companies Neckermann (then part of the eponymous department store chain) and Touristik Union International (TUI), the travel arm of the Federal German Railway. Local rival tour operator Berliner Flugring, which had begun as a consortium of 70 local travel agents arranging inclusive tour (IT) flights from West Berlin to holiday resorts in Europe, also chartered Saturn's (as well as a number of different British independent airlines') aircraft for its flying programme. When some British independent rivals in West Berlin began replacing their piston and turboprop planes with jets such as the BAC One-Eleven and de Havilland Comet 4 from the mid-1960s, Saturn's piston airliners became obsolete. To remain competitive