But what was air travel like before 9/11 and ATSA, and what actually changed? Before 9/11, airport security was outsourced to private contractors and was much less stringent than TSA's current standards.

No, the Transportation Security Administration (TSA) did not exist before the terrorist attacks of September 11, 2001. Prior to 9/11, airport security in the United States was a decentralized system managed by the airlines themselves, who typically hired private security firms to conduct passenger and baggage screening. These private contractors often had high turnover rates and varying standards of training. In response to the attacks, President George W. Bush signed the Aviation and Transportation Security Act in November 2001, which officially created the TSA as a federal agency under the Department of Transportation (later moving to the Department of Homeland Security). The transition "federalized" airport security, establishing uniform national standards, rigorous background checks for screeners, and more high-fidelity technology for detecting explosives and prohibited items. This shift marked the end of the era where security was treated as a private business expense and turned it into a core pillar of national defense.