Small planes outfitted with video cameras have been flying over Baltimore since January, capturing activity on the streets below and relaying the footage to police to help them catch criminals. The public knew nothing about it until this week — when Bloomberg Businessweek ran a cover story about the trial program. Airplane used to conduct wide area surveillance. Persistent Surveillance Systems The revelations triggered outrage from elected officials, defense lawyers and the American Civil Liberties Union, who said the program raised privacy concerns and could aggravate public distrust in a city that exploded in riots last year after the death...