[Character controller] run faster on slopes and jetpack

With what do you need help? First of all, you didn't say what kind of CharacterController you use. Is it the one from Standard Assets, or a custom one? either way, you should take a look at how it works and you will probably see that it has a grounded bool variable. You also know that each GameObject has a Transform component, and that transform.position is a Vector3 variable that consists of x,y and z. So you also know that you can read the y position. A CC also has a velocity which can be set according the movement mode of the character (running, walking etc.) as well as the gravity.

So, since you know (you could know, since it's all included in the CC) all these things, what is your question? :)