The boys find plans in a Boy's Life to make wings for a bicycle. Each wing was about 11 feet long.
First they set out to buy all the materials, 2x2s, #2 clamps, mueslin, plywood, etc.
It took 2 weeks to build the first wing and another week for the second one.
Finally they carried them out of the basement and hauled them the the local hill where they fitted them onto a bike.
Everyone tried to make it fly but none of them ever go off the ground. It was a total failure and the wings ended up in Flick's basement when they remained as a sad reminder until finally one night Flick's father threw them out.