Dave,
Did you notice the rule that disallows stored energy of any kind?
Back to the topic of saving the world from the energy crunch and global warming. Here is my thought:
We could do more for the world if we used our aero knowledge to improve surface vehicles by designing lighter cars. But the trend is heavier cars.
The danger of driving a 500 lb car is a big drawback. So I think it may be required that new ideas come from the aero side because we can fly light designs with little concern of a collision imbalance based on mass.
The freedom to design new aircraft could help lead the world.
Look at how Paul McCready continues to push the limits of efficiency. His craft are mostly impractical but he has shown what is possible. There is no reason for the rest of us to give up.