Intro: The Simplest Paper Airplane
Let me begin by saying this design of paper airplane is probably not the fastest design. This design is likely not the one that will carry a folded piece of paper the farthest. There's a good chance this way of making a projectile will not cause the sheet to hover for the longest possible time. Last but not least, odds are, this aircraft is not considered to be the single most visually captivating airplane ever constructed.
So why even make it then? The answer to that is simple-it's not the best in any of those criteria, but it it's well above proficient in all of them. Even if it's not the fastest, if you throw it hard enough, it will certainly fly fast. Even if it won't fly the farthest, it may well come close. Assuming it doesn't have the longest airtime, who cares? It'll hover for a good while if it's intended to. Lastly, even if it's not the single most attractive one, it most certainly does look good in a sleek sort of way. And that's great! After all, following a few throws, the pretty planes that are slaved over for so long adopt crumpled tips and dusty wings. After a few more, creases will begin to inhibit flight until soon, it no longer will be pretty or even functional. I mean, how many paper airplanes have you known to survive more than a few days of use? Then what's the point of spending so much time on them? And besides, there is another criteria that I haven't yet mentioned that shouldn't be underestimated. This plane is really easy. It's easy to make, as well as easy to remember how to make. If it gets lost or thrown away by some disapproving individual or ripped to shreds by some cruel sibling, a replacement can me made within seconds from memory. In many ways, that's the most valuable criteria of a paper airplane.
Step 1: Fold Paper in Half
If you remember it this way, this fold is in half, hot dog style. I would suggest lining up two of the corners and then creasing the rest from there if that makes any sense.
Step 2: Fold Corners In
Begin by taking one of the corners and folding it in so one of its edges lines up with the center crease. The crease should form an isosceles right triangle (one with two sides of the same length and a 90 degree angle). Do the same with the other corner closest to it.
Step 3: Basically, Repeat the Previous Step
As the heading suggests, you basically just repeat the previous step. Fold the hypotenuse (longest side) of the right triangle you just formed so it too rests on the center line. (Do this for both wings).
Step 4: Repeat As Many Times As Necessary
You could continue to fold in the same manner until the paper made it physically impossible to and you probably would still be left with a plane that would be fully capable of flying. The more you fold it, the smaller and denser your plane will be. The smaller and denser it is, the faster it will be able to fly. That being said, this kind will also drop faster. The fewer times you fold the wings, the less dense and more prone to gliding/floating it will be, but it will not travel as fast. Simply stop and use the last fold you made as the wings of the plane whenever you feel you have the dimensions you desire.
Step 5: Flight!
This step seems rather self explanatory. To get the plane to fly, throw it!
Still, I do have some basic pointers. Assuming you used a standard 8.5 in X 11 in. (21.59 cm X 27.94 cm) sheet of paper (or something similar), 3 folds for each wing will provide you with sort of a mix of a glider and a dart style airplane, whereas 4 folds for each wing will produce a dart style airplane. For the glider/dart style, I've found that a pinch grip at or around the balancing point is optimal (please refer to images above if confused). For the full on dart (4 or more folds per wing), a pinch style grip will work fine, but some speed can be gained if the index finger rests on the butt end of the plane and therefore, the grip is situated further back on the body of the plane. After accelerating the plane and releasing with the pinch grip, the index finger provides an extra boost. This style of throw takes more practice to master, and is something to practice if you are so inclined. Hope this instructable helped!