“It would, however, be entirely understandable why the government would be reluctant to reveal how many Lancaster bombers it actually had at its disposal on that particular night."
During WWII, against an enemy who had an Air Force and trained pilots.
So, am I to understand that ISIS has an Air Force that can down drones if they know how many there are ?
Don't think so.
There may well be some reasons for keeping the number of drones secret, but this comparison is not one of them.