What is the symbolic significance of the old man and his enormous wings? Why is the appropriate that the story contains almost no dialogue? How...

The author has chosen to make this a 3rd person omniscient point of view.  We as readers gain the thoughts of many of the characters, though never the old man.  The central focus of the story isn't so much the arrival and existence of the man, but how everyone reacts to him.  If the focus was the man, then the author would have provided details about his past and the nature of his existence.  Instead, we are meant to see how people treat him and how they explain him.  This gives clues to human nature.  Thus, dialogue is not important.  Behavior alone is important.  People lie often when they speak, but their actions have more truth.  Therefore, dialogue in this story would just get in the way.