Most of the world's airports are owned by local, regional, or national government bodies who then lease the airport to private corporations who oversee the airport's operation. For example, in the United Kingdom the state-owned British Airports Authority originally operated eight of the nation's major commercial airports - it was subsequently privatized in the late 1980s, and following its takeover by the Spanish Ferrovial consortium in 2006, has been further divested and downsized to operating just five. Germany's Frankfurt Airport is managed by the quasi-private firm Fraport. While in India GMR Group operates, through joint ventures, Indira Gandhi International Airport and Rajiv Gandhi International Airport. Bengaluru International Airport and Chhatrapati Shivaji International Airport are controlled by GVK Group. The rest of India's airports are managed by the Airports Authority of India.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What group took over the British Airports Authority in 2006?
Spanish Ferrovial consortium