BACKGROUND Joby Aviation are developing electric vertical takeoff and landing / eVTOL aircraft. Two of their pre-production 'S4' experimental prototype airframes have been registered with the FAA - N541JA Serial #JAS4-101 and N542BJ Serial #JAS4-202 (one of which was damaged in a crash last year) - as well as a sub-scale 55lb / 25kg Unmanned Aerial Vehicle / UAV: Joby's sub-scale eVTOL UAV in the hangar with a pre-production prototype S4 [Source: Kirsten Dirksen, YouTube -