The B-17 was a design of the Boeing Aircraft Corporation of Seattle, Washington. The designing was done in Seattle and the initial prodiction line was at the Boeing factory there. When the US entered WWII huge order flooded into Boeing for B-17s, and while production continued in Seattle, other B-17s were built under license by the Douglas Aircraft Company and by Vega (a Lockheed subsidiary). Over 12,700 were built.