Basically one of the coolest things you can make with a dollar.

Step 1: Water Bomb Base

The goal here is to make a water bomb base on one end of the bill. To do that:
-fold the bill in half hotdog style, then unfold (picture 1)
-fold the right top corner over to the edge of the bill, then unfold(picture 2)
-fold the left top corner over to the edge of the bill (picture 3)
-start to fold the open edge of the triangle back over itself (pictures 4 and 5)
-flatten and bring the other flap over (pictures 6 and 7)
-fold the flap back over so that each side has one flap (pictures 8 and 9)

Step 2:

Flip the bill over. Fold the water bomb base back, making sure to align with the hotdog style crease down the middle of the bill. Fold the bottom left and right corner in to meet the middle crease (pictures 3 and 4).

Step 3:

Fold over two little flaps (make sure to fold over more than I did in the picture, I had to adjust it later). Fold the left and right flaps in to meed the middle crease.

Step 4:

Fold the bottom piece up and then down to create a slight zig-zag and shorten the length of the model a little. Fold the entire thing in half.

Step 5:

Fold the wing and inner flap down, leaving a bit of space to be the body of the fighter. Repeat on the other side, keeping the wings even. Fold the inner flap up about half way and aligned with the edge of the bill (picture 3) and repeat on the other side.