Just about everyone alive at the time remembers where they were when they first heard about the terrorist attacks on September 11, 2001. I was 11 years old, sitting in my 6th-grade Social Studies class when someone said something vague about a plane hitting a building in New York City. As the day went on, we were dismissed from school early, and I went home and watched the coverage on TV with my mother. I remember the news playing the video of the North Tower crumbling into the cloud of debris over and over, and by the time I went to bed, I was afraid that terrorists were going to storm the beaches not far from my house.

I think it’s safe to say that the 9/11 attacks were a pivotal event in most people’s lives, whether they realize it or not. Many Americans cited the attacks as their reason for enlisting in the armed forces. For myself, watching the firefighters of the FDNY climb through rubble trying to find their lost comrades played a part in my decision to join a volunteer fire department later on. The attacks changed the lives and fates of every American that day, most especially the families of the 2,977 innocent people who were murdered.

9/11 also affected Americans through its impact on several American business sectors from air travel to entertainment. We may not realize it now, but repercussions from the attack irreversibly changed certain industries. Here’s a list of four industries that were transformed as a direct result of the September 11th attacks.

Airlines

The attacks forever changed the airline industry. Airport security was hardened almost overnight. The Aviation and Transportation Security Act was signed into law in November of 2001, and thus the Transportation Security Administration (TSA) was created.

According to the TSA, after the 9/11 attacks, the Federal Air Marshal Service (FAMS) was expanded to provide more coverage on board domestic flights, cockpit doors became reinforced, and every checked bag was to be screened for explosives. In 2002, the cockpit doors were further strengthened and were required to stand up against small arms fire and explosive fragmentation. The newly formed Department of Homeland Security (DHS) began the Federal Flight Deck Officer program during the same year, which trained pilots and other flight deck officers to carry firearms during flights.

According to Karen Walker, Editor-in-Chief at Air Transport World, the loss of friends and colleagues by airline staff coupled with the “new levels of vigilance” required of crew members created a “more stressful work environment.”

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Passengers were also somewhat hesitant to fly after the attacks, and according to Business Insider, the number of airline passengers fell by 2.7 percent globally in 2001. It took the industry two full years to bring passenger numbers up to the year 2000 levels, and since then the industry has been plagued by bankruptcies, restructurings, layoffs and a worsening of the “overall customer flying experience.”

Entertainment and Media

In the immediate aftermath film and television producers scrambled to scrub away images that could even remotely evoke the horrors of 9/11 and several productions were re-written to exclude showing airplanes, terrorists, and specifically the Manhattan skyline. Some television shows like The West Wing and Third Watch attempted to respectfully honor the victims and provide much-needed context to the American public.

According to an article on Vox, the entertainment industry as a whole struggled to adapt to the post 9/11 world, and for several years Hollywood avoided productions with overly dark imagery and excessive violence. The epic disaster movies of the 1990s immediately disappeared as producers felt that the public didn’t want to watch cities being destroyed on the big screen. Instead, movie studios focused heavily on family flicks and fantasy films.

Several years after the attack and the start of the Global War on Terror, movies about terrorism and war started to creep back into theatres, and eventually films about 9/11 itself and the wars in Iraq and Afghanistan were made, but it took a long time for movies such as Zero Dark Thirty and Body of Lies to enter the mainstream.

Healthcare

As a result of the scope and scale of the attacks, President George W. Bush signed Homeland Security Presidential Directives 5 and 8, creating the National Response Plan which was to be administered by the Federal Emergency Management Agency (FEMA), under the newly formed Department of Homeland Security.

Healthcare facilities, now dubbed Emergency Support Function#8 by FEMA, became better prepared for face both manmade and natural catastrophes.

“These directives also provided definitions for planning and response standards for all organizations, including private health-care providers,” wrote Mitch Saruwatari, co-chair of the development of the Hospital Incident Command System, in an article for govtech.com’s Emergency Management. “After that, hospitals became eligible for significant emergency management grant funds and resources made available through the Health Resources and Services Administration (HRSA). ”

Under these new guidelines and the new push for disaster resilience, hospital workers became familiar with the Incident Command System and the National Incident Management System, and healthcare administrators were trained to become defacto emergency managers in times of crisis.

Since the attacks, hospitals are much more resilient and most healthcare administrators know how to implement an incident command system. Regulatory agencies like the Centers for Medicare and Medicaid now require hospitals to adhere to national emergency preparedness requirements, which includes the simulated activation of the hospital’s emergency management plans at least once per year.

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Education

Many educators today are unsure how to teach elementary and high school students who weren’t alive at the time about 9/11. According to a report from NPR, less than half of the 50 states had “in-depth” curriculum regarding the attacks.

“I’d like to know exactly, like, everything that happened. Because I don’t know exactly how many planes there were,” said seventh-grader Josh Sylvester from Greenfield Middle School in Massachusettes when interviewed by NPR. “I know the two twin towers fell. But I don’t know if anything else happened.”

Thankfully, more schools are implementing 9/11 education as more teaching aids regarding the attacks becomes available. Still, many teachers avoid diving into the subject too deeply out of fear of sparking conversations about Islam, the Global War on Terror, and other related topics.

However, groups such as the National September 11 Memorial & Museum continue to advocate for a meaningful 9/11 curriculum and even offer seminars to prepare educators to teach students about the attacks. Ideally, future generations would learn about not only the attacks and the victims, but how the event shaped the world we live in today.