How to make a boomerang paper airplane

Step 6:Fold the bottom edge up along the crease you have see below.

Step 7:Fold the right-bottom corner to the left-bottom corner.

Step 8:Fold the edge of the folded part to coincide with the bottom edge.It forms a triangle with sharp corner.

Step 9:Pull up the triangle formed in the previous step and insert it into the bottom layer as shown below.

Step 10:Flattening along dotted lines of a1 to a2.Then turn over.

Step 11:Fold the left-bottom corner to the right-bottom corner.

Step 12:Fold the edge of the folded part to coincide with the bottom edge.It forms a triangle with sharp corner.