DURHAM, N.C.—It took Chuck Pell less than a minute to build his drone.

He folded a piece of paper 11 times, clipped on a battery-powered plastic propeller and rudder, then opened an app on his iPhone.

Next he flung the aircraft skyward, steering it above the trees with turns of his phone. The plane soared out of sight.

It's a good technology, according to Mr. Pell, who has suffered plenty of nose dives. It just "needs more pilot training."

Aerial drones have fought in wars, filmed movies and factored into the ambitious plans of high-tech executives who want to supply Internet service from the air.