The Federal Aviation Administration has granted approval for Amazon to test drone delivery, but don't expect a drone on your doorstep soon.

FAA will allow Amazon's logistics unit to use drones for research, development and crew training. But there are a lot of restrictions -- the flights must be conducted at 400 feet or below during daylight hours. The drone must remain within the line-of-sight of the pilot, who must have at least a private pilot's certificate.

Amazon has ambitious plans for a nationwide network of delivery drones, called Amazon Prime Air. But considering the legal and technical restrictions the FAA has placed on the technology, this latest announcement is a small step indeed.

In 2012, Congress ordered the FAA to integrate drones into the skies with passenger planes by September 2015, but observers say it's not likely that's going to happen. The FAA small-drones proposal, which is open for public comment now, is expected to take 18 months to two years to complete.

To get around FAA rules, Google's drone program is experimenting abroad and Amazon began testing in the United Kingdom last year.

But there may be a more practical way to use drones in delivery by combining them with the tried-and-true method: delivery trucks.

Mainstream media outlets such as Wired,Popular Science and "Car Talk" have been praising the HorseFly, an "octocopter" drone developed through a partnership between the University of Cincinnati and AMP Electric Vehicles, makers of the WorkHorse all-electric delivery truck.

Steve Burns, CEO of AMP, explains the process like this: The HorseFly will be positioned atop a delivery truck, awaiting a package from the driver. When loaded, the HorseFly will scan the barcode on the package, determine the path to the delivery address via GPS and fly away – completely self-guided – to the appropriate destination. Meanwhile, the delivery truck will continue on its rounds. After successful delivery, the HorseFly will zoom back to the truck for its next delivery run and, if needed, a roughly two-minute wireless recharge.

"Our premise with HorseFly is that the HorseFly sticks close to the horse," Burns says. "The fact that the delivery trucks are sufficiently scattered within almost any region during the day makes for short flights, as opposed to flying from the warehouse for each delivery."

After watching the video, the ironic thing that struck me about the HorseFly is the pairing of what seems like a fairly noisy delivery drone with the quiet of an all-electric vehicle. Nevertheless, this approach appears to have a number of advantages over the Amazon model.

As Wired put it: "There’s a big problem with the logistics of Amazon’s grand plan to deliver packages via flying drone: Sending swarms of aircraft from Amazon warehouses to American homes isn’t nearly as efficient as simply driving the packages on four wheels. But one startup’s plan to pair trucks with heavy-duty octocopters could make drone-dropped packages more than just a novelty. By working in tandem with delivery vans, drones have the potential to make shipping faster and cheaper than ever."

Meanwhile, over at Popular Science, writer Eric Sofge wrote, "HorseFly has one major advantage over Prime Air: it makes sense. From both a technological and logistical standpoint, Amp's truck-launched drone scheme is as level-headed about the realities of commercial, airborne robotics as Amazon appears to be ignorant of them."