How to hover using Keyboard/Mouse

Hi i was hoping there was a common questions thread, but here goes.

Is there a setting to check to lock in the amount of throttle being used, instead of tapping "w" repeatedly to maintain altitude (causes a bouncy ride)? I played a game where I could do this, and for some reason I can't replicate it. i don't think i ever turned on control assist.

Another example, I was using a joystick that has a slide adjust for throttle that makes things smooth (but i suck at aiming so i stopped using it).

thanks