It's a Tuesday afternoon at a small, radio control modeler's airport near Los Angeles, and the guy bent over his model Messerschmitt Me-109 looks serious. After a lot of fiddling, he squeezes gasoline into the little piston engine and connects his toolbox-cum-battery pack to the airplane. She's a beauty: deep forest green, meticulous iron crosses on fuselage and wings. "Flies for 16 minutes before