The Angled Cast is the primary cast, the maximum expression of the modern technique: it’s the right execution and "basic grammar" understanding of the dry fly fishing in its complexity. The ability to make this cast, is recognized in its execution simplicity, making simple the things that seem to be difficult.
The Overlapped Cast is perfect to penetrate beneath the vegetation or to cast the fly underneath an overhanging bush
The Flyby Cast is used to cast in high wind condition and where you can’t arrive with the Overlapped Cast, because is faster and you can cast more far.