While talks of future drone deliveries continue to mount, JLL retail experts report the retail industry may not realistically feel the impact of drone use for another 10 to 20 years.

There remain many logistics challenges surrounding the delivery of goods by unmanned aerial vehicles that currently prevent drones from making door-to-door deliveries on a large scale. Though drone deliveries make sense in markets with large stretches of land or even mountainous terrain or islands, JLL notes in its Retailers’ Guide To The Galaxy report, it is far more difficult for drones to navigate the infrastructure of more densely populated cities, which last-mile deliveries require.

JLL predicts drones will likely be used by retailers in stores before they are flying to customers’ front doors. Similarly to how drones are being used elsewhere in the commercial real estate industry, experts predict retailers will increasingly turn to drones within the next decade to secure warehouses and secure store perimeters through video, in addition to aiding in site selection and construction management.

Minor drone trials have been conducted in the industry. Convenience store chain 7-Eleven was the first to successfully complete a Federal Aviation Administration-approved drone delivery in July 2015. The retailer partnered with drone operator Flirtey to make the delivery, bringing doughnuts, coffee, a Slurpee and chicken salad to a family in Reno, Nevado, within a few minutes.

Last week the U.S. Patent and Trademark Office published an application from Amazon Technologies to build multi-level beehive-shaped towers for drone distribution and fulfillment. If approved, these towers would be built to support the distribution of products in densely populated cities, creating takeoff and landing platforms for drones. In its patent, Amazon said it plans to use 3D mapping sensors to coordinate flight paths and to prevent collisions.