Drone technology is rapidly evolving to service various scenarios on land, in the air and underwater (even underground.)
Number one commercial issue remains power sources and ability to sustain activities for longer periods of time without requiring a recharge.
MIT engineers recently attempted to extend the duration of an airborne drone using an expected method…gasoline. They created the Jungle Hawk Owl, a 24 foot wide drone that can be launched from the roof of a car and can stay airborne for 5 days on a single tank of gas.
Original ask by the Airforce was a solar powered device, but it appears solar lost quickly due to need to size of surface area, weight of batteries and challenges as you moved to latitudes far from the equator.