25 years later, 9/11 still shapes the way we fly. Here's how air travel changed after the attacks.

A TSA security checkpoint at John Wayne Airport in Santa Ana, California. Jeff Gritchen/MediaNews Group/Orange County Register via Getty Images Aviation security was completely overhauled after the terrorist attacks of September 11, 2001. The TSA, which federalized airport security, was established in November 2001. After 9/11, only ticketed flyers were allowed past security, and cockpit doors were bulletproofed. Flying has completely changed since Al Qaeda hijackers carried out the terrorist attacks of September 11, 2001, 25 years ago. The newly created Transportation Security Administration replaced the private screening checkpoints that flyers were used to and introduced a new normal at airports — one where water bottles are emptied, bodies are scanned, and goodbyes are said before reaching the gate. The planes were similarly hardened with bulletproof doors and the strictest protocols for cockpit access; pilots and flight attendants also received additional training to handle terrorists.