Global Hawk
© Associated Press / John Schwab/U.S. Air ForceAn Air Force Global Hawk unmanned aerial vehicle lands at Beale Air Force Base near Marysville, California.
Drones have been called the most hotly sought-after weapon system in a generation, but the robotic planes' primary role is to gather intelligence for the military.

The high-powered cameras that are slung underneath the planes allow soldiers on the ground to know what's over a hill or what's happening miles down the road: Spotting ambushes before they happen, noticing bombs along the side of the road, and observing bands of insurgents dug in along the mountainside.

But new sensors are being developed to enable flying drones to "listen in" on cellphone conversations and pinpoint the location of the caller on the ground. Some can even "smell" the air and sniff out chemical plumes emanating from a potential underground nuclear laboratory.

A story in today's Times examines the industry of building the cameras and sensors for the pilotless spy plane, many of which are built in the Southland.