Hughes H-4 Hercules (also known as the “Spruce Gooseā€¯) at Long Beach, California 1947.
This plane, the largest flying boat ever built and with the largest wingspan of any aircraft in history, is a prototype for an heavy military transport aircraft designed and built by the Hughes Aircraft Company. Due to wartime restrictions on the use of aluminium and concerns about weight, it was built almost entirely of birch.
Designed to be used during World War II, the H-4 Hercules was not completed in time. The aircraft made only one very brief flight on November 2, 1947 and the project aborted. Howard Hughes never really recovered from this huge failure, as large as the plane itself.