Reaching a gate for a commercial flight at a U.S. airport today typically demands a valid boarding pass, federal government security screening, and careful attention to the contents of carry-on luggage.
Air travel was not always so strictly regulated. In earlier decades, airlines used private contractors to operate security checkpoints. Full-sized shampoo bottles and cans of shaving cream were not confiscated for exceeding liquid limits, and friends and relatives could walk departing passengers straight to the gate to exchange goodbye hugs.
