Convergent evolution
Wings: the wings of insects, birds, bats and pterosaurs are similar to a certain degree. In particular, they are all thin and strong, with a wide surface area. The wings can be mechanically moved in a regular way so as to create lift; and so on. In each case the wings evolved separately, so their form reflects certain physical necessities. The three larger animals all have insulation and temperature regulation, and hence a high rate of metabolism. That is also necessary for flight, which requires a great deal of energy.