I love stuff like this! 😃
Think of it as Hot Coffee, but without all of the lawsuits and sex. Looks like some goofy Nintendo programmers slipped an Arwing fighter from Starfox into Ocarina of Time. A reader sent me this screen cap along with a link to the video. In it you can see Link spotting the spaceship. (Source)

You'll need a GameShark or other modding tools to access it, though. 😅