There are tools available to help reduce the threat, e.g. http://www.cunningrunning.co.uk/sam-pras http://www.cunningrunning.co.uk/sam-pras 'SAM-PRAS is a uniq

There are tools available to help reduce the threat, e.g. http://www.cunningrunning.co.uk/sam-pras http://www.cunningrunning.co.uk/sam-pras 'SAM-PRAS is a unique market-leading solution used by counter-terrorism agencies to identify potential MANPADS launch points within range of flight paths.' I don't work for or have any association with this company BTW, just aware of their software.