How do I disable air-control while jumping in a platformer?

Basically I want the player to commit to a jump when they hit the jump button, with very little to no in-air control.

Is there any way to adjust the level of control a player has while airborne?

if i understand what you mean, you can do this:

player is jumping ---- set player speed to 0

or

player is falling

else --- set player speed to 330

I've tried that. It doesn't seem to have any effect at all for whatever reason. The player object still has the usual amount of air control.

Thanks ramones, that link gave me the tactic I needed to get it sorted.