I had a flight A - B, B - A airports in my previous flying schedule and then I changed it to A - C, C - A plan, with the execution of a 3 days delayed. Now problem comes, before the first flight A - C of the new schedule starts, the plane would be finished at airport B and the worse is that the time slots of the old flight A - B and A - C overlap. As a result I have to cancel the flight A - B which causes such a loss. Even the time slots of both flights don't overlap, I still need to organise a transfer flight and it's very difficult to notice in the schedule chart.
Also, maybe the system can give a warning when the two successive flights arrive in and depart from different airports?
I doubt they'd be able to add a system check for each flight when it gets logged into the system or the ORS without bogging down the system even more than it is now.
The way I deal with this kind of situation is this:
* Go into the Flights tab of the aircraft you are going to change the schedule on.
* At the bottom, there should be flights that are booked but have 0 or very few passengers. Cancel a few flights at the end of the list so your aircraft ends up at your hub (airport A in your example).
* Go to the schedule and modify it as needed.
* Check back in 30 minutes to see if the flights are matched up correctly. If they're not, you can keep cancelling until the airports match up right.
It might seem silly to cancel flights, but in this way, you are not losing money (or not losing much at all) and you don't have the problem of fully booked flights cancelling three days later when your airplane is at the wrong airport and you have to scramble to get it to the right airport as quickly as possible. I've done that many, many times.
Also, try to replace the flights at the time they have already been flown that day. That will assure the replaced flights will be booked into system the next day at the time of those flights (if you activate with 3 days delay) and you minimize the risk of running into problem which you mentioned.
Also, myself I have a fleet group called "Verify", I put there planes every time I make schedule change etc. and I keep an eye on the flights every now and then. After the new schedule is already loaded properly (and any necessary outliers cancelled) and I am sure there will be no issues, I move the plane back to the respective fleet group where it belongs.
that's what I am doing right now, but when you have many planes and also the flights are only released when they come to exactly 3 days before departure, it's quite difficult to check.