The Significance of the Power of Flight in Comics

Since humanity's earliest days the ability to fly has long been one of the most innate yearnings of our species. This is reflected heavily in our fictional works, perhaps most noticeably in superhero comic books and films. However, not all heroes can fly (Besides the story's internal reasoning for their powers) what does this indicate about heroes who do have this ability and why? What does it say about those that don't? Comparison of multiple works may yield the most interesting results.