Berlin is served by one commercial international airport: Berlin Brandenburg Airport (BER), located just outside Berlin's south-eastern border, in the state of Brandenburg. It began construction in 2006, with the intention of replacing  Airport (TXL) and  Airport (SXF) as the single commercial airport of Berlin. Previously set to open in 2012, after extensive delays and cost overruns, it opened for commercial operations in October 2020. The planned initial capacity of around 27 million passengers per year is to be further developed to bring the terminal capacity to approximately 55 million per year by 2040.