Insect wings, unlike legs, are not appendages. They are specialized parts of the exoskeleton, particularly of the second and third thoracic terga. Terga are hardened backs of arthropod segments. Two sheets press together leaving, for strength, a network of tubular veins. The attachments and joints are complex. Since humans don’t have exoskeletons, we will never evolve wings like insects, fairies, or angels, only wings like bats.