It seems that when you're asked for a plane, you're expected to create a plane, not a wad of paper.

Presumably, this was during a unit on areodynamics, and the idea was to demonstrate an understanding of areodynamics, and not to show that you can throw balls farther than you can throw planes.

If the teacher had asked for the object that would go farthest, instead of specifically asking for a paper plane, then you would have a point.

1. There were no rules on what the 'plane' was supposed to look like. Creativity was encouraged and normally rewarded in this class (I liked the teacher a lot, actually, and was irked also because it was out of character for her to forbid thinking outside the box).

2. It wasn't during a unit on aerodynamics, and in any case, "the motion of air, particularly when it interacts with a moving object" is quite relevant to wads of paper, meteorites, missiles, arrows, helicopters, and various other objects that are not airplanes. It might have been a good opportunity to explore why something like my wad of paper would go farther than most planes, as well as the relative real world advantages of different things.

I have a similar anecdote from a summer camp as a kid. We were asked to build a tower from various materials. Points were given for the height of the tower, and subtracted for arbitrary "costs" of different materials (eg. a role of tape may cost 100 points).

I immediately realized that the costs worked in such a way that it was infeasible to build anything and come out positive, so I convinced my team to not build anything while we watched other teams go into the negative, while we calculating their debts.

It worked great until the teacher caught on and adjusted the prices so that it was cost-effective to build.

Step back a moment and ask yourself if the anecdote is really a case of a student not playing by implied rules. The teacher most likely had an idea of what they wanted to see students do but failed to make it clear. This was effectively a competition and, as is usual with competition, it's nice to have all competitors on the same ground.

Both sides have a point. I think a good teacher would have indeed separated this unusual entry from the main competition, because the other kids would have reasonably felt cheated by competing against something that's more a ball than an airplane. On the other hand, it's a clever hack, and deserves some acknowledgement. The appropriate acknowledgement depends on the kid; I know that if I did something like that, I'd probably either have some mischief up my sleeve or just want to disengage from the task as quickly as possible. The best way to have dealt with me, then, would be to acknowledge that I've got a clever trick, but that with all my spare time I should really construct something that has wings and flies, in the (implicit) spirit of the event.