Lesson Plans and Power Points
Get lesson plans for teaching your flight unit from Sciencekids NASA has complete lessons plans on the "Four Forces of Flight" for grades K-4 and for grades 4-6, including this board game.
eThemes from University of Missouri has pulled together some great resources for teaching Aerodynamics.
Get ready-made PowerPoint presentations on flight.
The Smithsonian has lesson plans for teaching about the Wright Brothers.
The Smithsonian also offers classroom activities related to the Wright Brothers.
The Exploratorium's Science Explorer has these activities for the budding aircraft designers:
Teach your students how to make a paper airplane.
Play with different birds' wings in this Airborne Experiment to learn about Bernoulli's Principle and other scientific principles that make flight possible. A great tutorial.
NASA has compiled a Beginner's Guide to Aeronautics, a very useful resource to help K-12 teachers with instruction and activities on all things related to flight.
Exhibitions and Explanations
There is much to explore at the interactive Kids.gov is the America by Air online exhibit from the Smithsonian's Air and Space Museum.
The Franklin Institute offers some unique resources on the Wright Brothers' experiments with airfoils and wind tunnels.
Here is another resource on flight aerodynamics and propulsion, including directions for making kites and model aircraft.