It doesn't happen now, after 9/11. 9/11 was a one-time thing, and basically ruined airliner hijacking forever for other would-be hijackers. Before 9/11, people were taught to comply with hijackers because it was just a political stunt and people generally didn't get hurt. After 9/11, passengers will now fight for their lives because they'll assume the hijackers are religious kooks who intend to murder them all by flying them into a building. A few hijackers with razor blades today will be torn limb from limb by the other passengers.