What if we used a combination of drone technology and powerlines...instead of a drone needing to have its own batteries on board, what if there was a power line suspended across the river that it ran along, similar to a street-car. The drone, let's say it holds 2 or 4 people per trip, would basically be a mini flying-on-a-line taxi. It would travel only along the power-line, thus no navigation or control systems needed, no pilot needed.Presumably it could have a much lighter frame due to no battery needed, and you could power it off the rapidly decarbonizing grid.
The downsides I see now are the safety risks if a part flies off, the noise may be intolerable, and you'd need to construct the lines and hold them up somehow. And obviously, you'd need to engineer the product and face the realities of the physics, which I don't know much about.