Forget about locks, levers and other devices that are designed to keep aeroplane doors secure, it’s simple science that makes it physically impossible for a regular person to crank one open, as AsapSCIENCE explains:
Using the largest commercial aeroplane, the Airbus A380 as an example, the main door measures [2.8m²], meaning [17,505kg] of force would be required to even begin to open it. To compare, this would be the equivalent of you trying to move three African bush elephants.
OK, then, what about the windows? Surely with enough power, you could smack one out? Nope:
It would be nearly impossible for someone to punch and break through an aeroplane window. These windows … can be made with up to six layers of various types of strong polymers and are bulletproof. Furthermore, these windows are almost always rounded to decrease drag while in flight, thereby preventing cracks and decompression.
So the next time you’re on a plane, don’t worry so much about the windows and doors, and more about what the in-flight entertainment is going to be.