Like electric model airplanes and drones, but larger. Battery energy density is not high enough (yet) to electrify long-haul jumbo jets, but we're beginning to see the electrification of small short-range aircraft.
They claim that these are less loud and less dangerous. Since this uses a shit ton of engines it means that multiple engines can fail before it loses lift. The reason why helicopters are loud as fuck is because the tips of the blades break the sound barrier. The blades in these engines do not go faster than the speed of sound. And unlike a helicopter this eVTOL has wings so when it is in flight the rotors don’t need to spin as fast as during takeoff so the engines make less noise.