Since their invention more than 100 years ago, airplanes have been moved through the air by the spinning surfaces of propellers or turbines. But watching science fiction movies like the “Star Wars,” “Star Trek” and “Back to the Future” series, I imagined that the propulsion systems of the future would be silent and still – maybe with some kind of blue glow and “whoosh” noise, but no moving parts, and no stream of pollution pouring out the back.
That doesn’t exist yet, but there is at least one physical principle that could be promising.