The camera swoops over the green expanse of the Everglades hundreds of feet below, like many helicopter shots you've seen on TV. But suddenly it dips and flies through a narrow, shaded canal where kayakers are paddling, and a viewer has to wonder, "How on earth did they fly a chopper in such a tight space?"

The answer: It isn't a helicopter. It's a drone.

Welcome to the world of radio-controlled, unmanned small aircraft for commercial use. When Amazon.com CEO Jeff Bezos said on "60 Minutes" recently that his company eventually plans to use drones to deliver packages, he created a buzz. But such aircraft are already used for limited commercial purposes.

Keith Colodny, owner of Precision Aerial Filmworks of Palm Beach Gardens, Fla., has used drones to provide promotional videos for real estate agents and car dealers, tourism campaigns, nature-focused TV programs and other clients. "And it costs a fraction of what a helicopter will cost for a full day," he said.

Brett Strand, sales manager for ReadyHeli.com of Jupiter, Fla., a distributor of drones, said he has sold 40 to 50 in the past six months, mostly to people who fly them as a hobby. But his business plan includes increased sales for commercial use and not just for advertising: "people who need to look at roofs, inspect power lines, farmers inspecting their fields, even fishing guides looking for where the fish are."

Military drones have been much in the news in recent years. The U.S. has used them to target and kill enemies in such places as Afghanistan, Pakistan and Yemen. In some instances, innocent civilians were killed by the missiles fired by the drones.

Strand, 39, does not call his units drones. The term used by the Federal Aviation Administration (FAA) for such civilian craft is unmanned aircraft systems, or UAS.

Military drones look like small airplanes and are controlled from hundreds or thousands of miles away. The products sold by Strand look more like small helicopters, anywhere from a few inches to 5 feet in diameter, and they have multiple rotor blades. The other important difference is the civilian craft can be flown legally only within the line of sight of the pilot manning the remote control on the ground. "And you can only fly them to a maximum height of 400 feet," Strand said.

The FAA has banned the use of drones for commercial purposes, at least so far. It has said it will issue guidelines in 2015.