Until the 80ties Munich was a provincial town. Only big companies were Siemens and BMW. It was not until the 90ties the Bavarian government had the plan to attract high-tech and finance companies to the Munich area. Together with the new airport, the growth limitations of the Frankfurt airport and the growth of the economy around Munich, it became attractive for LH to open their second hub in Munich.
Frankfurt airport was also important as it was half an US military base and half a civil airport. The majority of US service men and women arrived through Frankfurt.