Well-known aircraft manufacturer Boeing was granted a patent for a mid-air recharging system. Each aircraft or drone would be comprised of an electrically powered buoyant aircraft, a control system to maneuver the aircraft, and a retractable tether to couple the aircraft with a ground charging station. The aircraft would be able to disconnect autonomously when a call for a delivery is made.
In simplified language, it’s a blimp with a retractable cord like one might see on a vacuum cleaner, and the connector to the power station is like the magsafe cord on a laptop. The power savings in both the aircraft design and system methodology could potentially make it more practical for usage in deliveries.
One example found on The Next Web, postulates a zone-based pizza delivery system where drones can be launched from one location and re-dock at another from the same chain.
The patent language leaves plenty of room for adaptation with one or more thrust generators of indeterminate type, one or more control services, and one or more image capture devices.