Further, I have to agree with the two posters who mentioned Frederick Vallentich. I read about his account and it literally made the hair on the nape of my neck rise.
What about Richard Colvin Cox, the West Point cadet who vanished from the grounds in January 1950? He was never found. Such incidents as these do fascinate me, including the controversial ones including possibly fictitious people such as David Lang, Oliver Larch and James Worson. And, group vanishings, like the crew of the "Mary Celeste" are extremely unnerving.