[Kartographer]

They have been doing this in sereval cities

http://www.theblaze.com/stories/2013/01/28/military-conducts-another-massive-training-drill-involving-helicopters-this-time-in-texas/

http://www.theblaze.com/stories/2013/01/28/so-why-have-military-helicopters-been-flying-over-miami-we-explain-plus-see-the-videos/

[Sawdring]

There was one not long ago in Minneapolis as well.