Will self-flying planes transform the skies?

Will self-flying planes transform the skies? Image caption, Pyka's crop dusters are used in the US and Brazil Over an alfalfa field in California's San Joaquin Valley, a small crop-spraying plane is flying scarily low to the ground. There's little risk to humans though, as the plane is pilot-free. We can actually go lower than a human pilot can, says Russ Marotzke, as the aircraft skims over the crop. Flying lower means less spray drift and therefore less chemicals are needed than in conventional manned crop-dusting, he says.