Flying Dutchman

The Flying Dutchman is a legendary ghost ship that sailors believed was doomed to sail for all eternity, and served as an omen of the spectators' impending doom. First appearing in the 17th century, sightings would continue into the 20th century. Even England's King George V claimed to have seen the ship while on a voyage during his youth. While there are many stories of the ship, there is no evidence of it's existence. Those who saw the Dutchman claimed that it wasn't sailing, but flying above the ocean. The most widely accepted explanation for Flying Dutchman sightings is a phenomenon known as a Fata Morgana. A Fata Morgana is where a superior image (essentially a warped reflection) of an object in the distance is reflected on the horizon above it, resulting in a distorted, ghostly, floating image. It is believed this occurrence is what sailors saw, mistook it for a flying ghost ship, and the myth of the Flying Dutchman was born.

https://en.wikipedia.org/wiki/Flying_Dutchman
https://en.wikipedia.org/wiki/Fata_Morgana_(mirage)