How did the hijackers take over the planes on 9 11?

On September 11, 2001, the hijackers took over the planes by using box cutters and knives to threaten and overpower the flight crew and passengers. They gained control of the cockpits, taking advantage of a lack of heightened security measures for cockpit doors at the time. Once in control, they redirected the aircraft toward their intended targets, leading to the tragic events of that day.