The Hughes H-4 Hercules is a one-of-a-kind, heavy transport aircraft, built as a prototype by the Hughes Aircraft company during the 1940s. It made its first flight in 1947 but the project never developed any further than this. Constructed from wood due to the wartime restrictions on aluminium, the craft is nicknamed “Spruce Goose” and is the largest flying boat ever built with the largest wingspan of any aircraft in history. It is now conserved at the Evergreen Aviation Museum in McMinnville, Oregan, USA.