Wikipedia

Aircraft stability and control is a fascinating field.

Their maneuverability is owed to the fact that they’re somewhat unstable to begin with. It’s been literal decades since I had the class, but a good way to think of the difference between a fighter jet and a commercial jet (maneuverability wise) is that a commercial jet’s stability is like rolling a small ball in a large bowl. You’ve got a lot of leeway on what you can do before the ball won’t eventually end back up in the center of the bowl. A fighter jet is the opposite… it’s like trying to balance that small ball on top of a basketball. If you place it perfectly, it will stay in place. A touch off center, it will begin to drift further off center faster and faster until it falls off completely.

That’s why it takes so much training and physical fitness to fly fighter jets. It’s almost like they’re actively trying to kill you. And that’s not just the modern computer controlled jets like the F-35 and F-22. The older jets were like that too, but I have to imagine less so. An F-18 can’t pull a 9g turn… the F-22 can, and I also understand it can fly itself while the pilot is unconscious for a few moments after that 9g turn…