OK, so two gliders and one towplane (J-3) made the list.
From a AOPA (USA) poll this date:

Poll result:
Which of the following aircraft would you most like to fly?

P-51 Mustang 66.49%
J-3 Cub 12.79%
SpaceShipOne 10.59%
Robinson R66 6.92%
Grob G103 glider 3.21%

I have no idea on how the poll was conducted nor who was asked.