Magical Realism is the blending of fantasy and reality. This style is a cultural aspect of Marquez's native Columbia and is a notable genre in other Hispanic cultures. In this story, the blending of fantasy and reality serves to question notions of truth and fiction.
Marquez plays with uncertainty and this mix of the miraculous with the "every day" gives the reader a challenge in trying to make sense of what is real and what is not. In the end, there is no clear indication of the differentiation between reality and fantasy. This literary style allows the author to stretch the imagination and gives the reader an unconventional reading experience wherein he/she must deal with the uncertainties. Thus, the reader is forced to "wonder" and this is 'wonder'fully imaginative but also frustrating for a reader who wants things spelled out logically.
In the story, the couple and the people of the town debate whether or not the old man is an angel. They seem to ignore the fact that, regardless of whether or not he is an angel, there is an old man with wings. In fact, the doctor thinks that the man's wings are so "natural" that he wonders why more people don't have them:
What surprised the doctor most, however, was the logic of his wings. They seemed so natural that he couldn’t understand why other men didn’t have them too.
In the end, the old man's monetary cache is trumped by a spider woman, another instance of magical realism.
Here is one interpretation that deals with a way that magical realism is used in a critical respect. If this story is interpreted as a critique of commercialism and materialism, the elements of magical realism illustrate how mindlessly people pursue monetary gain. Even though they have a miracle (angel or 'natural' man with wings) on their hands, they treat him as an annoyance unless he is bringing them money. This shows how single-minded people can be and how they might miss miraculous things in life, not to mention the opportunity to be generous and caring.
Portraying the old man as an angel or winged, Marquez shows how thoughtless and unimaginative people can be when they are too concerned with the trivial things.