One of my theories about the show is that things were supposed to go a certain way but Ben kept interrupting it and doing things the way he wanted them to happen. Him turning the frozen donkey wheel instead of Locke is a great example of this. I think if they did change the past the plane would still crash (which ben had nothing to do with?) and things would get done the way then were supposed to. That could be the plot of season six.
The very short teaser they showed for season six was the shot of jack lying in the jungle which might mean this is how the final season will open. That might mean my prediction will come true.
