Amazon is looking at drastically reducing its delivery times—to 30 minutes or less— as it plans a new service called Prime Air that it says could debut in a few years. The giant online retailer plans to use semi-autonomous drones to carry purchases to customers. CEO Jeff Bezos announced the plan Sunday on CBS’60 Minutes.

Bezos tells Charlie Rose that Amazon’s “octocopter” could be airborne within four to five years, using GPS coordinates to find customers.

The drones would depart from the retailer’s “fulfillment centres,” the huge warehouses it has built near many large population centers in the U.S. and elsewhere. They can carry about five pounds, Bezos says, a figure that covers around 85 percent of Amazon’s products.

The delivery drones would be particularly useful in densely populated urban areas, Bezos says. Powered by electricity, their current range of operation is around 10 miles from the point of origin.

Writing that “drones can explode, or run into things,” the Quartz technology blog’s Heather Timmons notes that safety concerns may limit where the new delivery devices could be used.

In addition to safety concerns, drones could face another challenge before they’re widely used for delivery: overcoming the possible suspicions of citizens who have mostly seen the unmanned aircraft mentioned in conjunction with military and surveillance uses.

Rose’s interview of Bezos also touched on the retailer’s 10-year, $600 million contract with the CIA, through its Amazon Web Services unit. The company is using its technological expertise to build a computing cloud for the agency, Bezos said.

When asked by Rose if that presented a conflict, Bezos answered, “We’re building what’s called a private cloud for them, Charlie, because they don’t want to be on the public cloud.”

Amazon isn’t alone in pursuing drone delivery. Earlier this year, a pilot project by Domino’s Pizza looked at flying hot pizzas to customers in Britain, posting a video of a successful test run.

That led the site Singularity Hub to observe:

“So why are drones such a big deal? In our robotic future, anything that can reduce urban congestion, minimize carbon emissions, save money and save trips to the emergency room (car accidents kill, you know) will drive huge value in the economy and make our lives better, to boot.”

What does the phrase “save trips to the emergency room” (Para. 11) mean?