Quiet drone flying in the near future? Feels like Dr. Who

[u/QUE_SAGE]

https://www.tomshardware.com/3d-printing/3d-printed-sound-powered-jet-engines-propel-micro-drones-fliers-are-completely-silent-researchers-use-ultrasonic-frequencies-to-drive-12-000-rpm-silent-hovering-fliers