Making airplanes, being successful

One day it was my turn to teach a 4-H group at camp.  There were about 30 children in the class to make airplanes.
To prepare, the night before I went through my house and picked every type of paper I could find to
make airplanes.  There was some paper provided but so often that is the same old thing.  One paper I picked was cupcake papers.  I tried several times to make an airplane from it.  I had no success so this was a good choice to let the brain create. 
I like to teach a class on something I do not do well.  This encourages students, especially children, to try something new.  I told the students, age 9 to about 14 or 15 that I could not get the cupcake paper airplane to work and did not know if it would work. 
Three of the older boys in class assured me it was alright because I was right it just would not work.  Their Dads worked designing airplanes.  The best airplanes were made by a couple of the younger boys using the cupcake papers.
My purpose was not just making airplanes.  I told them to never let someone tell them they could not do something just because the other person could not understand how to do it.