Imagine ordering a package online and receiving it just 30 minutes later -- by an unmanned helicopter.

Amazon.com (AMZN) raised eyebrows late last year by revealing such a vision as part of a secret program code named "Octocopter."

"One day, seeing Amazon Prime Air will be as normal as seeing mail trucks on the road today, resulting in enormous benefits for consumers across the nation," the e-commerce giant said recently.

Related: Amazon to FAA: Let us fly our drones

This delivery-by-drone plan still requires years of testing and approval from the FAA, which bans non-recreational use of drones in the U.S. without approval.

Drones obviously don't play a role in Amazon's current business, but it's easy to see how they could be a game-change for this e-commerce juggernaut.

NEXT: Boeing