Berlin is a city in Germany. The city has ratings ranging from 150-250 in most games. Tourist ratings are slightly higher than business ratings.
The default airport is Berlin Tegel Airport (TXL).
Berlin has fairly good ratings for a European city. This, along with most players prefering nearby Frankfurt or Munich, makes this a good place for your first hub. There may be mild to moderate competition, but the city can generally sustain it. The city can connect to many major European cities such as London, Paris, Istanbul and even to Asian cities such as Beijing with adequate range planes.
Berlin Tegel Airport usually achieves a status of Level 6 or 7 by the end of the game. As such, buying the airport is not recommended unless there are no better options available. Additional airports will rarely achieve a status beyond Level 1 or 2 and should not be built.
Large planes such as the Airbus A380 are optimal on high-occupancy routes to distant cities. For routes to nearby cities, use medium-sized planes. Small-sized planes are not recommended unless early in the game as they will depreciate value.