By the early 90's, the number of passengers going through Hanover Airport climbed to over 4 million per year so that the existing Terminals A and B had already reached their projected capacity for the end of the 90's. A further challenge was the World Trade Fair EXPO 2000 and its expected additional passenger traffic, so that the decision was made in 1994 to commission contracts for design and consultancy services for the extension of the airport.