"A Very Old Man with Enormous Wings" is a great example of magical realism, a style most often attributed to Marquez. So, the first notion of hybridity is between reality and fantasy. Magical realism is the blending of reality and fantasy often to the point that the reader is challenged (and often frustratingly so) to come up with some explanation for events occurring in a world where the line between fantasy and reality is uncertain or gone altogether. This is what Pelayo, Elisenda and the rest of the townspeople have to do as well. As odd as it is to have an angel, or a winged human, in town, they eventually come to treat it as if it were an odd, but normal event. This is, of course, after they give up trying to understand the old man because he does not fit their traditional/superstitious beliefs about angels and he defies all other description.
The "very old man" is also a hybrid of ambiguity himself, at least in the eyes of the townspeople and the reader. We don't know whether he is a real angel or just a human with wings, some science experiment gone wrong (or right), etc.
The style (fantasy/realism) and the character himself (angel/man) both employ hybridity. But this hybridity should be thought of as ambiguity as well because the line (/) between the different elements of the hybrid is blended. The world of the story is magical and real; it defies description of being just one or the other. It is both. The very old man "with enormous wings" might be an angel and he might not. This style of writing implores the reader to wrestle with ambiguity; it is an exercise of reinterpreting notions of reality and fiction.
One of the key phrases is the "logic of his wings," a phrase the doctor uses to describe the very old man's wings. This is a clear indication of the conflation (hybridization) of magic and logic. The doctor even goes on to say that the wings are so logical, he is surprised that more men don't have them. That is, the (magical) wings are so logical, he thinks all men should be so magical/logical. The story ends with Elisenda watching him fly away, transitioning from a real "annoyance" in her life to "an imaginary dot on the horizon of the sea." He is real and imaginary.
This style of writing and hybridity can be confusing but it is meant to provoke thought and, potentially, new perspectives on traditionally held beliefs, concepts and the art of reading itself.