Whilst it is tempting to blame Failing Grayling [as the Labour Party have done 21st Dec] for the local difficulty at Gatwick Airport, it is pointless to do so. Setting an exclusion zone of 100 km would make no difference. Regulations are pointless at preventing, only for prosecuting.
This problem was ALWAYS going to appear and the people who have shown themselves utterly unprepared are the Board of Gatwick Airport Ltd. and Chief Operating Officer Chris Woodroofe. What's the bet they will not be fired and still get their bonus?