You know the trick where you move ground units to unwalkable terrain in order to stop them from moving? Do that, except move the air units to a location blocked by other air units. IE. Put a big group of lifted terran buildings in a corner and try to move the air unit to that corner. The air units won't 'fit' in the area, so instead of moving, they will just stop. Doing this will prevent the air units from moving, but will not prevent them from attacking.