Amazon.com Inc. has been granted a new patent by the U.S. Patent and Trademark Office for a delivery drone that can respond to human gestures.

The concept is part of Amazon’s goal to develop a fleet of unmanned aerial vehicles that can send packages to customers in 30 minutes or less. Issued this week, the patent may help Amazon grapple with how flying robots might interact with human bystanders and customers waiting on their doorsteps.