The low energy density of batteries favors large planes and short distances.
The only reason you are seeing them in small planes is that electric propulsion makes VTOL viable, and VTOL favors small planes. There is just this niche in aviation that can't be filled at all by fossil fuel engines, so it's the first to adopt electric ones.
And yes, regulations will be the most important factor for those. I imagine it all depends on how silent those planes can be. But I doubt safety will be the limiting factor.
The only reason you are seeing them in small planes is that electric propulsion makes VTOL viable, and VTOL favors small planes. There is just this niche in aviation that can't be filled at all by fossil fuel engines, so it's the first to adopt electric ones.
And yes, regulations will be the most important factor for those. I imagine it all depends on how silent those planes can be. But I doubt safety will be the limiting factor.