On the evening of October 21st, 1978, Frederick Valentich piloted a plane over the Bass Strait and planned to land in King Island. He radioed the Melbourne Flight Service to let them know there was a large aircraft passing over him. Frederick mentioned that something was hovering over him and suddenly, the communication ended. Frederick and his aircraft have never been found, but many people believe there was a UFO that abducted him. Many UFO sightings were reported in the area that Frederick disappeared from.
Website:
Drinking The Cool Aid
Resources:
The Baffling Disappearance Of Frederick Valentich (allthatsinteresting.com)
Disappearance of Frederick Valentich - Wikipedia