How To Make A Paper Airplane

MATERIALS NEEDED:
1. One sheet of paper. Common notebook paper or stationery should work quite well.
The paper used must be rectangular in shape with straight, smooth edges and square (90°) corners. In order to provide the necessary stiffness and ease of folding the paper's weight should be at least 18 pound but not more than 28 pound paper. The size of the paper is less important than the features already discussed. It may range from about 4x6 inches to about 11x14 inches (lighter weight paper is more suitable for smaller sheet sizes).
The "weight" of paper offers an approximation of how thick and how stiff each sheet is. The term actually refers to the weight of a stack of 500 sheets of paper (of a certain size, which I have forgotten; possibly 17x22 inches?).
2. A smooth, flat work surface.
The work surface should be at least as large as the sheet of paper and offer a firm, stable surface to support the paper while it is being folded.
3. OPTIONAL: One pair of scissors or paper shears.

PROCEDURE:

Fold the paper in half lengthways. Crease this fold well, then reverse it (open up the folded page and fold it along the same line in the opposite direction; in other words, turn it inside out) and crease again. 
This fold is the foundation of all that follows and it is important that it is done properly. Ensure that the long edges of the paper are carefully aligned so that they are flush with one another over their whole length before creasing the fold.
Step 1

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Fold down the top left corner until the top edge of the left half of the page is aligned with the first fold. 
Step 2

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Fold down the top right corner until the top edge of the right half of the paper is aligned with the first fold. 
Step 3

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Fold the point down. Steps two and three form a "point" at the top of the page. Fold this point down (toward you) so that the flaps formed in steps two and three are on the inside of the fold. Make the fold as high up on the page as possible without folding or crushing the flaps which are on the inside of this fold. 
Step 4

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Fold in half lengthways (along the original fold from step 1) towards the back so that the folded-down point is on the outside of the fold. 
Step 5

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Tear or cut a notch in the upper corners. If you have scissors available they will provide an easier and more attractive way to make the notches. Remove a square (about ½ inch) from the outer corners. Make sure you do not cut your notch along the center fold. 
Step 6

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Open the fold from step five so that the point is again on top and pointed toward the bottom of the page. The notched corners will be at the top of the page. 
Step 7

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Fold down the top left corner so that the top edge of the left half of the page is aligned with the center fold. This step is very similar to step two. 
Step 8

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Fold down the top right corner so that the top edge of the right half of the page is aligned with the center fold. This step is very similar to step three. 
Step 9

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Fold up the tip of the point to hold the flaps in place. Steps eight and nine created two "flaps" which expose the tip of the point (which was created in steps three and four) through the notches created in step six. Fold the exposed tip of the point up so that it covers the edges of the two flaps. This will hold those flaps in the proper position during flight. 
Step 10

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Fold the right side of the page back along the center fold so the the flaps and point are exposed on the outside. This creates two panels folded back-to-back along the center fold, with the notches and upturned point on the outside of the fold and the inside faces of the panels being smooth. 
Step 11

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Rotate the page clockwise 90° so that the angled portion is to the right and the square end is to the left. 
Fold down the right wing. This fold lifts just the top panel created in step 11 and folds it "in half" so that the angled upper edge of the panel is parallel to and even with the original center fold (now at the bottom of the page).
Step 12

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Flip the page over, left to right so that the fold created in step 12 is down against the work surface and the angled edge is at the top and left and the square end (now possibly with the protuding tail of the wing created in step 12, depending upon the length-to-width proportions of the original sheet of paper) is to the right. 
Fold down the left wing. This fold is a mirror image of the one just completed in step 12. The angled edge is folded down so that it is parellel to and even with the original center fold.
Step 13

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The plane is now finished and ready to fly! 
Here is a side view and a top view of the plane after step 13 is completed and the plane is allowed to "open up" naturally.
Finished Plane

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