Asymmetric folding yields twelve inch wingspan from eleven inch sheet of paper. Three-finger grip flip yields thirty to forty foot flights.
Step 1
Take an 8-1/2 x 11 inch sheet of paper and make four marks labeled A B C D around the edge. A and C are 1-1/2 inches from the edge, B and D are 1 inch from the edge.
Flip the paper over and duplicate the marks; you should be able to see through the paper. This will make it easier to line up the marks when you fold the paper.
Step 2
Bring B to A and C to D, and holding the paper in place press the fold to a crease. Be careful and don’t let the paper shift while you press it flat.
Now fold in half (a mountain fold),
flip over, and fold each side in to the center. The plane from the front is a W. 
Unfold and lay flat. It should look like step 2, with three folds. Now fold in half the long way so the leading edge meets the centerline.
Open this back up and fold the leading edge about 1/4 inch in.
You will be folding this over and over until you reach the fold you made in the picture.
Fold up the plane into a W again and press the folds hard to tighten them up.
Unfold the plane and you are ready to fly. Curl up the trailing edge tips to provide a little up elevator. Adjust the wingtips up or down to balance the flight. Flatten out the W a lot and the glides will be lengthy. Some tape on the overlaps and leading edge fold also helps.
Your middle finger is below the centerline at the back of the plane, and the two adjacent fingers grip the plane. Flip your wrist to launch.
For legal-sized paper 8-1/2″ x 14″, use 1-3/4 inch as A and 7/8 inch as B. This flies with great authority.