> It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil,[1] or in a few cases the downward thrust from jet eng

> It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil,[1] or in a few cases the downward thrust from jet engines. OK so in that case the paper airplane is an aircraft provided that you fold it to have an airfoil. Done. https://www.youtube.com/watch?v=_Dof_Ks-f9U https://www.youtube.com/watch?v=_Dof_Ks-f9U Also, if it needs to have a power source, the rubber band helicopter or the rubber band airplane is super legit. That's a power source. My point isn't that I really think that these are aircraft. It's that trying to apply the rules for "mechanical devices which carry people in them" to things which don't carry people is pretty silly.