How would I correctly add air control with my momentum script?

Hey there! I’m making a script that makes you keep your momentum in the air, but I have a problem: I cannot get air control to work.

This is what I currently do:

currentVelocity = currentVelocity+humanoid.MoveDirection/2

But this just makes you fly into the direction you are moving. How would I fix this? Any help is appreciated!