Fine. You authorize the whole crew, not by fingerprint and not by code, but by voice recognition and secret code words per person. Then you allow the override to be overridden by a majority (recursively). Sounds way better than making the door break when a majority of people kicks at them. It is faster than remembering and entering codes, and cannot be overridden by one sick authorized person. An attacker would have to control the whole crew to make them do what he wants, to a level where they actually speak the secret words. In an event where the crew anticipates a crash, giving in on pressure would be the worst option to take.

To prevent attackers from muting all but the required majority of crew members, sensors all over the plane must be able to record any emergency code words spoken in the event of an attack, which will enact certain security measures (depending on the code word could lock or unlock the possibility to enter the cockpit, notify air security etc). This system should of course not be able to be deactivated.

And if you really wanted to make things sure, you could install majority-authorization buttons on every seat setup to be pressed by a percentage of boarded people within a period of mere seconds, which would allow the people on the plane to make a decision. For an attacker it is not possible to make all those people press the button, since he would not know who is not complying.

Of course you can also have some remote mechanism of unlocking, although the security implications of remote authorization and transmission of commands would be complicated to get right and open too many attack vectors.