Aircraft blueprints are available to view and download at The-Blueprints.com. AviationShoppe.com, Etsy and eBay sell blueprints. All four websites feature blueprints of aircraft from various eras.
The-Blueprints.com offers more than 6,600 blueprints from more than 38 manufacturers, including Cessna, McDonnell-Douglas, Lockheed, Boeing and Antonov.
AviationShoppe.com focuses its blueprint selection on military aircraft, principally from World War I and World War II. It offers blueprints of aircraft from more than just the U.S. Air Force; British, Japanese, German, Italian and Russian blueprints are available.
Etsy's selection includes framed blueprints, posters of blueprints and loose-leaf blueprints for purchase. Its selection, as of March 2015, leans toward World War II-era aircraft.