Step 1: Does it actually work?-Yes!
I teacher engineering in high school and this is a project I do with my classes. If a ninth grader can build a working boomerang so can you. Still don't believe me, take a look at the video proof. (Note the plans are for a righty, the student in the video is a lefty he reversed the plans so it would work for a lefty.)
Step 2: UPDATE! The Plans and the material
UPDATE: I have saved the plans as a PDF File this should correct the printing issues. You will still need to select print full size or 1:1.
Material-the plans call for 1/4" 7 layer marine grade plywood, this plywood is hard to find. Baltic birch plywood has 5 layers and it will work great for this project. It can be found at craft stores, lumber yards, or ordered online. My students have had good results with other types of 1/4" plywood but baltic birch works the best.
Step 3: What tools will I need?
You could also carve your boomerang, but I do not have the patience for that.