According to Wikipedia, it was a paper helicopter toy that sparked the interest of the Wright Brothers. link.
In 1878 their father, who traveled often as bishop of a regional church, brought home a toy "helicopter" for his two younger sons. The device was based on an invention of French aeronautical pioneer Alphonse Penaud. Made of paper, bamboo and cork with a rubber band to twirl its twin blades, it was about a foot long. Wilbur and Orville played with it until it broke, then built their own. In later years, they pointed to their experience with the toy as the initial spark of their interest in flying.
Myopic view of cool, papercraft