“The sky’s going to be dark with these things,” said Chris Anderson, the former editor of Wired, who started the hobbyist Web site DIY Drones and now runs a company, 3D Robotics, that sells unmanned aerial vehicles and equipment. He says it is selling about as many drones every calendar quarter — about 7,500 — as the United States military flies in total.

The burst of activity in remotely operated planes stems from the confluence of two factors: electronics and communications gear has become dirt cheap, enabling the conversion of hobbyist radio-controlled planes into sophisticated platforms for surveillance, and the Federal Aviation Administration has been ordered by Congress to work out a way to integrate these aircraft into the national airspace by 2015…

Aside from the missing persons mission, experts here outline a number of uses for the planes: “precision agriculture,” with tiny planes inspecting crops several times a week for the first sign of blight or insect invasion; safety missions by semiautonomous flying machines that could cruise the two-mile length of a freight train and examine the air brakes on each car, far faster than a person could, and be available for accident assessment in case of derailment; inspection operations of pipelines or power lines, a job that is notoriously dangerous for helicopters, and scouting out fires or car crashes.