Black helicopter alert

‘Night Chopper Flights Over L.A. Are Tied To Military Training': Sure, that's exactly the cover story Jack Bauer would use. The Los Angeles Times reports: 

The Black Hawk helicopters, which have appeared nightly for almost a week, have attracted the attention of residents as they hovered over downtown landmarks like City Hall, or maneuvered quickly between office skyscrapers on Bunker Hill. Though many residents speculated that the diving and climbing helicopters were part of a movie shoot, authorities confirmed Wednesday that they were part of a joint exercise."

Sure. Just a military exercise, m'am. Move along.