As well, the sector of control system in berlin means that there were traditionally three airports open in the city, each serving only a part of it. Once germany was reunited, these three airports split berlin air traffic to the point where no one became dominant.

They're closing two of the airports soon (TXL and THF) and expanding SXF to become the primary airport for the region. but because of history, it will never reach the size of FRA or MUC.