The nature of both creatures has been debated over the centuries. Angels began in the Old Testament as anonymous messengers of God but evolved, through various religions, as immortals of the heavenly realm.
Fairies, on the other hand, tend to be associated with pagan myth and folklore. They are generally thought of as supernatural beings who live alongside humans, possibly within a slightly different dimension to ours. Fairies are either immortal, or extremely long-lived, and come in a variety of usually humanoid shapes and sizes.