Crap fails,in trek they even go there.Bleh you aren't having fun with the fantasy. Who says a jetson type car has to be under constant forward propulsion that if unmanned will dive to the ground? Get all star trek on us. I know you have ideas. :wink
One episode a shuttle looses power abd Picard is injured,nearly dies.I could go into reaction control thrusters are minI ion engines uses by the voYager craft.