"A boat? A plane? A bit of both in fact. The Soviet 'Ekranoplan' was one of the more obscure products of the fight for technological supremacy in the Cold War. In September 1966 an American spy satellite flew over a Soviet naval base on the Caspian Sea and took a series of photographs. This being the height of the Cold War, the results created quite a stir among the American intelligence community, because they showed an object, more than 100m long with inexplicably stubby, square wings, quite unlike anything they had seen before." More info at BBC: news.bbc.co.uk/2/hi/uk_news/magazine/7638659.stm