This is just another one of my planes. I've already made about 5 of the "bullhorn" and I have the design totally memorized, so I decided I'd share it with everyone. I hope you enjoy it.
Step 1: Basics
Start with any piece of paper, it doesn't matter what size. Take the top right corner and fold it down to make a right angle triangle, unfold. Do the same with the top left corner, unfold. You should have a big x in the middle of your paper . Now fold the top of the paper down to where the x goes of the paper, unfold. Flip over.
Step 2: Pop It
During the last step you should have flipped your paper over at the very end. Now push in the middle of the paper where the two lines form an x so the sides "pop up." Pull in the sides to form a triangle with a rectangle underneath it. Crease down the paper. Now fold the top layer of the triangle up on the right and left sides to make two small triangles on top of the bottom layer triangle, (sounds confusing but you'll get it if you look at the pictures.)
Step 3: Giving It Wings
Fold the left and right ends of the paper in to the center crease on the paper, each one should make a half trapezoid. Now fold half of that same fold back out to the new crease. Fold the paper in half. Now fold down the wings (as shown in pictures below.) Make sure to fold down the triangle along with the wing to form an even smaller triangle. Do the same on the other side.
Step 4: Horns
Now there should be two small triangles sticking out of the front of your plane. Fold each one up a little to the main crease line to make an even smaller triangle. Now you have your horns and your plane. When you through it make sure you hold it close to the nose. Have fun flying!