This is how to make the fastest paper airplane I've ever seen. I call it the Eagle.
Step 1: Fold in Half
This is an easy step. Just fold an 8.5 x 11" sheet of paper in half down the center like pictured, and then open it up again so that it lays flat.
Step 2: Fold the Cockpit
Fold the cockpit of your paper airplane so that the flap corners meet at the center line.
Step 3: Fold the Cockpit Down
Fold the cockpit down so that the point lines up with the center fold line.
Step 4: Fold the 2nd Cockpit
Fold your second cockpit by folding your tow flaps down like the 2nd step.
Step 5: Make the First Folds of the Wings
Fold another two flaps down to the center of the plane.
Starting to look like a real paper airplane now!
Step 6: The Second Folds of the Wings
Flip the airplane over and fold each side in to line up with the center fold of the plane.
Step 7: Ready for Takeoff!
Flip the plane over one last time and open up the folds so that you have the 'body' of the plane to hold on to (like pictured).
You are now ready for a test flight.
To fly well, fly inside and throw as hard as you can.
DISCLAIMER: DO NOT THROW AT AN ANIMAL OR HUMAN BEING.
Step 8: Bonus Step
If you want your paper airplane to go even further, put a paperclip on the forward body of the plane. The weight will help it fly farther.