General aviation accounts for three-quarters of U.S. air traffic, from small propeller planes to large jets, operating among nearly 19, 000 airports. While most security operations are left to private airport operators, the Transportation Security Administration (TSA), part of the Department of Homeland Security (DHS), provides guidance on threats and vulnerabilities. The intelligence community uses standards of reasonableness to evaluate individuals for nomination to the consolidated terrorist watchlist. This book presents actions taken to strengthen areas of aviation security while also presenting new passenger screening technologies.