After 9/11, US airports tightened security, restricted sharp objects and gate access, reinforced cockpit doors and saw passenger demand fall sharply.Prefer HTon Google The terrorist attacks on the World Trade Centre on September 11, 2001 significantly changed air travel and airport security in the US and the world over.The US aviation industry experienced a sharp drop in passengers of roughly 30% after 9/11. (Unsplash)Launch of the TSAThe US centralised airport security policy with the creation of the Transportation Security Administration (TSA) in November 2001. Before 9/11, airports and airlines individually used to strike deals with local private security companies but this arrangement made way for a federal agency taking over recruitment. Today, the TSA has around 65,000 employees—50,000 are responsible for direct screening of passengers and luggage.Also Read: The wrong turn that US strategy took after 9/11Crackdown on sharp objectsMetal detectors and X-ray machines have been part of airport security since the 1970s. Rules and implementation for carry-on baggage were lax until the 9/11 hijackers were found to be carrying pocket knives and box cutters. Subsequently, airports have required most sharp objects to be kept in checked baggage only, limiting their usage as potential weapons.Tickets and ID for entryPre-9/11, any member of the public could go through airport security checkpoints until the boarding gate to see off or greet travelling friends and family. Since 2002, only ticketholders with valid ID are allowed past security—except for unaccompanied minors who require an adult guardian to escort them to the boarding gate.Also Read: What Donald Trump said about his building just hours after 9/11 — and what followedPilot safetyCockpits were easier for passengers to access, with flight attendants often encouraging children to visit mid-flight. In light of the hijacking, however, the US’ Federal Aviation Administration (FAA) mandated that airlines install bullet-resistant cockpit doors. By April 2003, all airlines had satisfied this rule. Cockpit visits before takeoff or after landing are still possible on some airlines but up to the pilot’s discretion.Also Read: Drones Recreate Twin Towers Over New York Ahead Of 9/11 Anniversary In Emotional TributeDrop in travel demandThe US aviation industry experienced a sharp drop in passengers of roughly 30% after 9/11. While some of this was caused by businesses freezing all non-essential air travel, the American public largely perceived a greater risk associated with flying. Airline revenue was decimated and mass layoffs took place—United Airlines filed for bankruptcy in December 2002. The industry didn’t recover until at least 2005.Raghav Bikhchandani is a Senior Content Producer at Hindustan Times, where he conducts research for stories and specials across multiple beats for the editorial desk and the Page 1 team.