Glider
Captain
I know that this is possibly one of the best kept secrets in that a lot of people believe this is happening but no one has ever had any hard evidence, but this might just be a crack in the secrecy.
http://news.bbc.co.uk/1/hi/programmes/newsnight/5079044.stm
http://news.bbc.co.uk/1/hi/programmes/newsnight/5079044.stm