Which is airport is located in German and second busiest airport in Germany and operates a dense domestic and European network as a member of Lufthansa Cityline? 
Lufthansa CityLine: Lufthansa CityLine GmbH is a German airline with its headquarters on the grounds of Munich Airport. Munich Airport:  It is the second busiest airport in Germany in terms of passenger traffic behind Frankfurt Airport, and the seventh-busiest airport in Europe, handling 42 million passengers in 2016.
Munich Airport