Thanks to a combination of good design and physics, it's very unlikely that someone could open an airplane's door during flight. Many aircraft doors are larger than the openings they cover, and even when this is not the case, the immense difference in pressure between the inside of an airplane and the air outside would require a massive amount of force to get the door open. Continue Reading
There was one famous case in which a hijacker named D.B. Cooper managed to jump out of a commercial aircraft in flight during the 1970s, but this isn't something an average person could do. Cooper forced the plane's pilot to depressurize the cabin, which allowed him to open the door.
Because of the September 11th hijackings, it is highly unlikely that an airline passenger would be able to gain access to the plane's cockpit in order to demand that a pilot depressurize the cabin. In most cases, passengers who attempt to open airplane doors midflight seem to be agitated, disturbed, and not thinking logically. In spite of numerous passengers' attempts, it would take superhuman strength to open an aircraft door in a pressurized cabin.Learn more about Airplanes & Helicopters