FAA issues flight restriction over Ferguson, Missouri, "to provide a safe environment for law enforcement activities" – @ABCaviation
— ABC News (@ABC) August 12, 2014
Apparently police requested the flight ban after a police helicopter took small arms fire. The ban means local news stations won't be able to cover events on the ground from their helicopters.
UPDATE: The AP filed FOIA requests with the FAA for audio recordings of conversations with St. Louis police officials pertaining to the no-fly zone declaration. The recordings "show that local authorities privately acknowledged the purpose was to keep away news helicopters during violent street protests," AP reports.