The following web sites may help you in your
research.
How Airplanes Fly
Look for your definitions here:
Your Own Flight: Forces of Flight
Great site about the history of flight and explains the four forces of flight.
How Airplanes Work
Simple to very technical explanations
Principles of Aeronautics
Terrific site, with history, myths, sports and more.
What is Aeronautics?
Experiment! Change the angle of attack, thrust, and elevator and see how far you can throw a paper airplane in this neat simulator.
Flight Simulator:
Other Interesting Sites:
Merriam-Webster's Collegiate Dictionary
NASA's Beginners Guide to Aerodynamics
Directions for Paper Airplanes