A drone-racing ace charts his own course as the sport goes mainstream. Carlos Puertolas maneuvers an X-shaped drone high above a grassy field in a Los Angeles park, then spins it sharply to face the ground and sends it full-throttle into a suicide dive. He takes his hand off a radio controller and peels off a pair of opaque white goggles. Puertolas is an aloof but unassuming Spaniard who stands about 5?8?, with a tuft of gray in his bangs and a rough chinstrap beard. In his day job he's a top animator at DreamWorks, but he's in this park testing a model designed especially for him by the Florida drone-kit company Lumenier.