The writing style in the story is very simple and direct, and so similes are rare. Two of the most important concern the angel; he is not a gleaming figure of holy light but instead a very human creature without obvious supernatural abilities. The wings are not composed of fairylight, but dirty and missing feathers, very practical and disappointing.
...that pitiful man who looked more like a huge decrepit hen among the fascinated chickens.
The angel went dragging himself about here and there like a stray dying man... Elisenda shouted that it was awful living in that hell full of angels.
(Márquez, "A Very Old Man with Enormous Wings," salvoblue.homestead.com)
These similes show how the angel is probably not anything supernatural, but instead just a living human with wings, different than the normal humans to which the village is accustomed. This is not an extraordinary fact, since the world in the story contains some form of magic, as seen in the spider-woman. Describing the angel as "like a huge decrepit hen" shows his flaws and gives the impression that he is not actually connected to a heavenly realm; on the other hand, it is possible that the human understanding of the heavenly realm is idealized, and in fact it is as human and flawed as the Earthly realm.