What makes a good airplane?

As a researcher and future designer of paper airplanes, you and your partner's job is to search the Internet to discover the principles of flight. How do planes fly? What causes them to take off? Is it the speed? The wings? Both? Is there more than one theory? What are the important laws or principles behind flight?

Once you have researched the principles, you must research how to build the perfect paper airplane. Does it make a difference what you make it from? How you fold it? Do you put a fin on it? How do variations of wing size and weight affect flight?