Ultralight Aircraft National Air and Space Museum

The concept of gliders propelled by small engines emerged in the 1920s, but didn't rise in popularity until the 1970s. 

The Smithsonian National Air & Space Museum

Collection - Kelch Aviation Museum

Smithsonian Displays Smallest Airplane - FLYING Magazine

The AC-35 Autogiro could fold back the rotors and switch engine

Exciting New Partnership with the Evergreen Aviation & Space

Steven F. Udvar-Hazy Center National Air and Space Museum

Aeronca L-3B Grasshopper > National Museum of the United States

航空宇宙博物館・別館 くーま、DCを行く。8日目 : くーまくーま・旅のはなし

Steven F. Udvar-Hazy Center National Air and Space Museum

Great aviation museums—Northeastern US - AOPA

The Mitchell U-2 Superwing Showed How Versatile an Ultralight Can

Smithsonian National Air & Space Museum Udvar-Hazy Complex

List of aircraft in the Smithsonian Institution - Wikipedia

New additions to Chile's National Aeronautics and Space Museum – LAAHS

Smithsonian hosts GA fly-in - AOPA