Eileen Sullivan

Scores of low-flying planes circling American cities are part of a civilian air force operated by the FBI and obscured behind fictitious companies.

The Florida postal carrier charged Thursday with two federal crimes for steering his smallgyrocopter through protected Washington airspace "literally flew under the radar" to the lawn of the Capitol, Homeland Security Secretary Jeh Johnson said as key lawmakers raised alarms about security risks.

Counterterrorism officials are chasing a credible but unconfirmed tip that al-Qaida has plans to set off a car bomb in New York City or Washington around the Sept. 11 anniversary. It was the first word of a possible "active plot" timed to coincide with commemoration of the terror group's attacks a decade ago.