The venerable Piper Cub. Thousands of returning servicemen from WWII learned to fly thanks to the GI Bill, in the Cub and others
similar such as the Taylorcraft and Aeronca Champ. I used to lay in the grass in my backyard in the late 1940's and 50's watching
these yellow Cubs being put through their training maneuvers by the student pilots. That sparked my lifelong interest in aviation.