As mini-copter slips through DC defenses, many ask: How?

By brazenly flying a mini-helicopter through Washington's no-fly zone and landing it on the US Capitol lawn, a 61-year-old pilot stunned the security world and prompted the question: Why wasn't he detected? The city essentially became fortress Washington after the 9/11 attacks of 2001, when the military added Humvee-mounted Avenger missile launchers, intensified aircraft detection systems and integrated air security operations. A huge hovering radar blimp casts a protective eye over th