Taking a commercial flight from a U.S. airport generally requires a boarding pass to get anywhere near a gate, security screening controlled by the federal government and careful attention to the contents of carry-on bags.
It wasn’t always this way. Travelers once passed through security checkpoints staffed by private contractors selected by airlines. Full-sized bottles of shampoo and cans of shaving cream didn't get tossed for exceeding liquid limits. Friends and relatives could accompany departing passengers and exchange goodbye hugs at boarding time.
