Folklore
"The People Could Fly" is a textbook example of folklore.
After all, it's a story about magical happenings in the past, it details a historical reality through a fantastical lens, and—most importantly—it was created through oral tradition. In fact, the version we're talking about is just one of many, and no two are identical. But you don't have to take our word for it, click here and here to see what we're talking about.
As much as "The People Could Fly" is about slavery and the experiences of enslaved people, it's also about the idea of folktales. The closing section refers to how "the slaves who could not fly told about the people who could fly to their children" (32), just as the narrator does for us. That places us, as readers, into the tradition, too, passing the baton our way to then pass on again. And that right there, Shmoopers, is how folklore works in a nutshell.