This is really cool. I thought of doing this myself, but it is too expensive for now. Randall Fishman built an electric ultralight. He is now selling them as the ElectraFlyer. Depending on the battery pack and propeller installed, it can fly for up to two hours. Instead of the short noisy propellers on most ultralights, the ElectraFlyer is available with a long carbon fiber propeller. I also found out that Sonex has been experimenting with electric versions of their airplanes. Between gas prices and global warming, one of these planes may be the only way I get to fly again.