Anatomically, the human arm, the flippers of seals, and the wings of the birds are the forelimbs containing similar bones.
These forelimbs have a common origin and similar anatomical features but have been modified to perform different functions.
Flippers allow the seal to swim, birds fly using their wings and humans perform a variety of functions using the arms.
Such structures are homologous to each other.
The wings of insects are anatomically different.