Actually I am only working on D-AAGE as this was the regular Plane which had no Schedule and now it's charter, so there are no regular A319.
But for that I am analyzing very much Schedules of Air-Child, where I can see gaps where no gaps should be (e.g. Thu-Mon A321, there could be an A319 to fill this gap, because when on all other week-days (Mon, Thu, Fri) an A321 is filled there would be ensurely enough guys want to travel on the two other week-days), only for the weekend this is quite hard to guess where gaps are needed to be filled, because there are only saturday and sunday and those are much more different as the most weekdays (at Mon-Fri you have relative constant Traveller-Count, on Friday more because the weekend-traveler)...