During a segment airing on CBS’s 60 Minutes, Amazon CEO Jeff Bezos revealed to correspondent Charlie Rose the latest development out of Amazon’s R&D lab, two small “octocopter” unmanned aerial systems (UAS) designed to pick up and carry packages directly from Amazon’s sprawling network of fulfillment centers directly to customers’ doorsteps within 30 minutes of the user placing an order. The service — called “Amazon Prime Air” — could debut as soon as 2015, though it will likely take a bit longer to iron out the technical challenges, Bezos said.

“The hardest challenge in making this happen is going to be demonstrating, to the standards of the FAA, that this is a safe thing to do,” Bezos told Rose during the segment. “I don’t want anybody to think this is just around the corner, this is years of additional work from this point.”

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The reality is not so simple, however. Right now even small UAS like the ones being developed by Amazon cannot be operated outside of line of sight of the operator, and the FAA has yet to say what would have to change for that requirement to be lifted. Further even these small UAS — which can weigh as little as five to 10 pounds — have a limited battery life in the half-hour range, with 45 minutes to an hour being at the very high end. That battery life is further reduced as the payload grows heavier, creating a difficult technical challenge that continues to hamstring small UAS applications.

Then there’s the larger questions of safety and reliability that will have to be addressed first by the FAA and then demonstrated by small UAS manufacturers, including Amazon, which is opting (at least for the time being) to develop its UAS fleet itself within Amazon’s R&D labs. There are several prototypes in the lab beyond the one demonstrated on 60 minutes, a company rep told Fortune via email, so the future might end up looking quite a bit different than the one Bezos unveiled to the world last night.

An optimistic estimate is more like four to five years, Bezos said, which should grant both the Federal Aviation Administration and Amazon time to figure out just exactly how such a system would safely work. Under the FAA Modernization and Reform Act of 2012, Congress mandated that the FAA open up U.S. national airspace to small drone traffic, including for civilian and commercial operators. (Right now only specially authorized government and academic institutions can fly UAS in the national airspace, and commercial use of UAS is prohibited.)

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However, few within the aerospace community are confident that the FAA will meet that deadline. Ensuring safety is both a regulatory and technical challenge, and FAA authorities have yet to provide guidelines on how commercial drone operators will be certified, policed, and audited for safety, not to mention how other issues of responsibility like liability and insurance (there will be lots and lots of insurance) will be resolved. That puts UAS developers at a disadvantage as they wait to see what kinds of drones will be allowed to fly in this new drone-enabled airspace.

But according to Bezos, Amazon’s R&D team is pressing ahead with plans to reduce delivery times for members of its $79-per-year program to just half an hour, at least in selected areas that are near enough a fulfillment center to allow for it. A short video screened by Bezos during the 60 Minutes segment shows packages snaking their way through one of the company’s labyrinthine warehouses — one of the nearly 100 that Amazon has scattered across the map — before being deposited in special standardized yellow containers and sped along a conveyor belt until one comes to rest underneath the belly of a waiting Amazon octocopter. The drone latches onto the container and whisks it skyward, traversing an idyllic countryside before depositing it gently outside the recipient’s house.

In reality the transition to drones as commercial tools might not be quite so seamless and easy, but Bezos is convinced that services like Amazon Prime Air are the future. “It will work, and it will happen, and it’s going to be a lot of fun.”