I took part in the 50th Anniversary of the D-Day Landings where nearly every Head of State and political leader of the countries involved attended.
How did the French deal with the security of all these targets and the airspace? They set up restricted airspace, issued transponder codes and set up live Air Defence batteries! Interesting flying around and watching the launchers track you. If you were stupid enough to ignore the publicity about the proceduress, too lazy to comply or a terrorist who doesn't follow the rules you got shot down.
I will leave the topic open for discussion.