I read from fly-by-night to flying fish.

I definitely didn't remember that a "dope" is a "thick sauce" so now "fly dope" makes more sense!

https://www.oletimewoodsman.com/collections/the-ole-time-woodsman-fly-dope-story

https://www.etymonline.com/word/dope

Here is my Notre Dame and fire juggler Paris Timelapse:

https://www.youtube.com/watch?v=x-PV2hx6CaQ&ab

It seems most likely that the Flying Dutchman is just a mirage of some kind...but  ...