THE PORT Authority of New York & New Jersey has ordered the pulling down of Terminal 6 at John F Kennedy (JFK) International Airport. The terminal, designed by I M Pei and opened in 1970 for National Airlines, was the first in the world to include glass window walls. The building consists of two cylindrical satellites for boarding and deplaning and an open area that proved flexible when Boeing 747s were introduced while the terminal was still under construction. In later years it had become home to Delta Air Lines for transcontinental flights and finally JetBlue. It became vacant on October 22, 2008, when JetBlue moved to the new Terminal 5 at JFK.