During the annual Leipzig Trade Fair, which at that time was considered the most important meeting place for businessmen and politicians on both sides of the Iron Curtain, Lufthansa and Interflug were granted special permits to operate flights between Leipzig and West Germany. In 1986, Lufthansa and Interflug applied for joint traffic rights for year-round scheduled intra-German flights over the Iron Curtain, which was initially rejected by the Western Allies (probably due to concerns that their unique market position for flights to and from Berlin might be weakened), and only granted in August 1989. As a consequence, Interflug launched flights on the Leipzig-Düsseldorf route, with Lufthansa serving Frankfurt-Leipzig. In 1990, Interflug flights from Dresden to Hamburg and Cologne were added.