Hi all, have searched on here but can't find anything ...

I got notified on Thursday 5th October that the BA2796 LGW - AGP on Sunday 8th October was cancelled, they could only offer a flight at 8:45am on the Sunday morning (refused to rebook on a Vueling flight around the same time), and so as that was a significant difference in timing, I've emailed to claim appropriate compensation.

BA have written back to me stating that that flight was cancelled

"Your claim's been refused because BA2796 on 08 October was cancelled because of airspace restrictions. On the day you were due to travel, Air Traffic Control restricted operations out of/into a block of air space your aircraft needed to travel through. I’m afraid this was out of our control and caused unforeseen disruption to our schedule."

Does anyone have any insight as to what might have gone on here, would a random block of airspace be closed days in advance that left BA with no choice but to cancel the flight 3 days ahead ?
Thanks folks

Ed