>>Parts such as the propellers are produced using 3D printer units

Interesting that they haven't taken advantage of the recent work coming out of MIT for quieter propellers. Some detail on toroidal propellers here, the TL;DR of which is they dispense with propeller tips where a good bit of noise and inefficiency (vortices) come from.

BTW/FWIW, toroidal props are starting to appear as an option for watercraft. They’re expensive to manufacture as they’re typically bronze, but they drop fuel consumption 20-ish percent.