I don’t think so. While the 3rd dimension seems to grant more freedom and space to move, each vehicle uses more energy/payload, so you will need more vehicles, which in turn fill up the newly won space. Also, in unclear/dangerous situations a vehicle in the 2D-plane can safely stop. In the air, they can’t. This solutions will be restricted to special circumstances and us cases, not for day to day business in my opinion.

Do you have any references that uav can move a mass with less energy use or pollution? As far as I know they would use more. flight can be more efficient but usually only if its a long distance because take off and landing is energy intensive. Drones fly somewhat like helicopters though which I was under the impression was one of the most energy intensive travel means. as far as I know, good to bad wise, its like walk - bike - train - bus - long flight - car - short flight - ships (mainly I think do to how they are powered. sailing or electrified may be way better) - and helicopter would be at the worst level of pollution.