After the fall of the Berlin Wall in 1989, and following German reunification in 1990, Berlin once again became the German federal capital; leaders made plans to recognise the city's increased importance by constructing a large commercial airport. The existing airports — Tegel, Schönefeld and Tempelhof — were ageing and becoming increasingly congested with rising passenger numbers. To ensure the economic viability of the project, they pursued the single airport concept: the new airport would become the sole commercial airport for Berlin and Brandenburg. They planned to close Tegel, Schönefeld and Tempelhof upon opening the new airport, then ban commercial aviation from any other airport in Brandenburg. On 2 May 1991, the Berlin Brandenburg Flughafen Holding GmbH (BBF) was founded, owned by the states of Berlin and Brandenburg (37% each) and the Federal Republic of Germany (the remaining 26%). Eberhard Diepgen, Mayor of Berlin, became the first chairman of the supervisory board. The holding company announced on 20 June 1993 that Sperenberg Airfield, Jüterbog Airfield and the area south of Schönefeld Airport, where the evaluation of the locations Sperenberg, Jüterbog East, Jüterbog West, Tietzow, Michelsdorf, Borkheide and Schönefeld South was carried out according to five criteria with different weighting. Each site was advocated by various factions in the ensuing political discussion. With regard to land-use planning and noise pollution, rural Sperenberg and Jüterbog were considered more suitable for construction of a large airport. Economic considerations favoured an airport located near the city centre, with existing road and rail links (as is the case with Schönefeld). On 28 May 1996, Mayor Diepgen, Minister-President of Brandenburg Manfred Stolpe and Federal Minister for Transport Matthias Wissmann committed to Schönefeld as the site for the new airport. This so-called consensus decision was later affirmed by the respective state legislatures. The new airport would use some infrastructure, such as a runway, from the existing Schönefeld Airport. Originally, BBF anticipated that the new airport would be owned and operated by a private investor. They called for proposals, which led to two bidding consortia emerging as serious contenders. One was led by Hochtief through its Hochtief Airport subsidiary and included ABB, Fraport and Bankengesellschaft Berlin as partners. The other consortium comprised IVG, Flughafen Wien AG, Dorsch-Consult, Commerzbank and Caisse des Dépôts. On 19 September 1998, BBF announced that the Hochtief consortium were the successful bidder. This saw them granted exclusive authority to negotiate the terms and conditions for an acquisition of the Berlin Brandenburg Airport holding and the construction and operation of the new airport for 50 years. On 31 March 1999, BBF officially commissioned Hochtief and its partners to construct the new airport, causing IVG to file a lawsuit. The Brandenburg Oberlandesgericht acknowledged the concerns voiced by IVG. In its review, it found that in certain points the assessment of the applications had been biased towards Hochtief. This led to annulment of the contract award on 3 August of that year. Hochtief Airport and IVG teamed up and created a plan for a joint bid on 10 November 2000 in an attempt to receive the contract to construct and operate the new airport. At the time BBF hoped that the planning approval could be completed in 2002, with the tentative opening in 2007. When Hochtief/IVG submitted its bid in February 2002, the BBF board consisted of Manfred Stolpe, who would become Federal Minister of Transportation; Klaus Wowereit, who replaced Eberhard Diepgen as Mayor of Berlin and chair of the board; and Matthias Platzeck, who replaced Stolpe as Minister-President of Brandenburg. The board determined that the proposal would not be practical and voted 22 May 2003 to scrap the privatisation plan.