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.