The bigger internal fluvals can be adjusted too.
Generally, if it can, its pretty obvious how (knob on top or flow regulator on side).
With regards to the air flow, you need to ensure there is a venturi tube. This pokes out of the filter into the air above, and as the filtered water is rushing past the pressure sucks air in creating bubbles in the water flow.
Generally these can be adjusted with caps or knobs too.
However, all is not lost if this isnt the case, the hole can be covered somewhat so regulate the water/air flow, I dont know what you could use, but it would have to be non toxic (blu-tack?!)
HTH