As a state-owned company of East Germany, Interflug had the important role of securing foreign exchanges, as the national East German mark was considered a weak currency. For most of its existence, Interflug was not a member of the International Air Transport Association (IATA), and therefore could significantly undercut ticket prices of other European carriers. From the 1970s, an increased effort was put on operating chartered flights to Mediterranean and Black Sea holiday resorts, many of which specifically catered to West Germans (as travel restrictions applied for East Germans). From the 1970s, Interflug gained traffic rights to several destinations in Western Europe. All of these flights could be booked at travel agencies in West Berlin and West Germany, which had signed sale contracts with Interflug. To simplify the transfer of passengers from West Berlin to and from Schönefeld Airport, a dedicated border crossing checkpoint was inaugurated at "Waltersdorfer Chaussee", and scheduled shuttle buses were operated from the Central Bus Terminal in the Westend locality.