Glasgow airport lies 8 miles west of Glasgow city centre an is within easy reach of the rest of Scotland. The airport was orginally used as an overspill for the RAF base at Renfew. BAA purchased the airport from Glasgow corporation in 1975 and began immediate development, expanding the terminal building and raising the capacity to 3.5 million. BAA continued to develop during the eighties with a £ 55 million expansion increasing the capacity by 70% to 6 million. Today Glasgow airport is the buisiest of Scotland's three main international airports, with over 8 million passengers passing through each year.