Many who are unfamiliar with Agile Project Management confuse it with "winging it." They couldn't be farther from the truth.
While "winging it" is putting complete faith in chance, Agile Project Management relies on frequent prototypes and immediate adjustments. It's the ideal way to control a complex and/or uncertain project, without making the false assumption that everything can be planned up front.
Here's a good article from Agile Attitudes that explains more about the differences between Agile development and "winging it" ...