One major change in naval aircraft during the Second World War was the development of a single-seat strike fighter that could take on both the role of dive-bomber and torpedo-strike. In the U.S. Navy, this development led to the Douglas Skyraider, one of the most successful naval aircraft ever built; in the Royal Navy it resulted in the Westland Wyvern, surely one of the most frustrating naval aircraft ever built, an airplane that took ten years to bring to fruition, that was declared obsolete within four years of its initial arrival on British decks.