Fairy tales:
Fairy tales often don't have any fairies in them at all. In terms of the kinds of human characters the stories are peopled with or the structure of the stories themselves, there isn't much difference between folk tales and fairy tales. But the presence of witches, dragons, trolls, magic spells, or other magical elements help distinguish fairy tales from folk tales.
Both folk tales and fairy tales may involve a character learning an important lesson. Both may put the heroes in mortal danger. Like folk tales, fairy tales may serve as cautionary tales to teach their listeners what not to do.
Some fairy tales have roots in the oral tradition, but others, called literary fairy tales, were made up and written down, so technically, these are not folk tales. However, they may share many of the same traits as fairy tales from the folk tale tradition.
Like folk tales, fairy tales in their original forms often have less than happy endings. Because the stories were invented to be instructive and cautionary, they often feature a main character who suffers for his or her failure to do things the "right" way. Little Red Riding Hood talks to a stranger in the woods and gets eaten by a wolf. In the original story, that's the end of her. No woodcutter comes along to save her. In the original version of Cinderella, the wicked stepsisters cut off their toes to try to fit their feet into the glass slipper, and then on the way back to the castle after Cindy and the prince are reunited, birds come along and peck out the stepsisters' eyes! Ouch! Folk tales and fairy tales are meant to disturb you and teach you to be careful. They may entertain you, but on the other hand, they may scare you. In Irish folklore, fairies are not like Tinkerbell. They have a dark and dangerous side and can make you very sorry if you cross them. The modern, cleaned up versions of fairy tales you may have read as a youngster may be very different from the original versions of these stories. But I won't go into that here because I want you to be able to sleep at night!