
The flying mechanic works very differently in all of the Mario games. The raccoon tail in Super Mario Bros 3, the cape in Super Mario World, the flying cap in Mario 64, the red star in Mario Galaxy and most recently the helicopter suit in New Super Mario Bros.
The SMB3 loving kid in me wants to say that Raccoon Mario is the most awesome thing ever, not only was it the original but also easy to use and super helpful. Since it's so awesome I want it in every Mario game. Or at least until I think about it some more and start to understand why Nintendo constantly changes the flying mechanic. Each new Mario is very different and the ability to fly high in the air can easily break the games finely tuned difficulty.
The way the raccoon tail allows Mario to fly over almost whole levels makes it very overpowered. But it works in SMB3 since that game is all about giving the player a massive amount of short levels. If the player flies over a few of them it's not really a big deal, there are so many of them and the player will soon get to a level where the raccoon tail is all but worthless.
Mario World on the other hand has fewer levels but much larger once. Levels Nintendo seems to have worked on forever until their level design and difficulty reached almost perfection. The cape is hard to control making it much harder to simply fly through half the level. Which is probably why the younger version of myself never liked it much. But as I grew older and wiser I start to realize how the raccoon tail would have broken that game. It needed to be neutered, resulting in the less awesome cape.
Then we have the flying cap in Mario 64. That games was all about exploring 3D environments and giving the player an unprecedented sense of freedom. The flying cap fits in perfectly with this theme, allowing the player to freely fly around and experience these amazing 3D environments.
Mario Galaxy on the other hand was a much more linear experience then Mario 64. It was no longer about exploring 3D space, instead it guided the player through a set path thereby making sure that the game never slowed down and got boring. Constantly serving up new and cool stuff. The flying cap wouldn't have worked in a game like that, instead we were given the red star. It never played a huge part in the game, instead it was just one of the many action packed roller coaster rides the game was filled with.
You might think that the raccoon tail would have worked in New Super Mario Bros. That game more then any other felt like a new SMB3. And it probably would have in single player. But since the game was also made to work just as well in co-op having one player fly forward at full speed wouldn't have worked. Instead the helicopter suit allows for quick vertical movement but very slow horizontal movement, making sure the other player isn't left behind.