Isle of Grain Airport. Maybe not the best idea...
Information from Rodney Chambers, Leader of Medway Council on the BBC Kent website: The Isle of Grain is home to one of the world's largest liquefied natural gas terminals, a few miles a sunken American warship laden with high explosives, London Array wind farm being built nearby and the airport cuts through an area that is home to 100,000's of migrating birds.
Apart from that, it's an ideal place to build an airport.