Everybody always prefaces their theory. I will keep this short. Hopefully, people are willing to expand upon the one general idea that I'm suggesting.
Nuclear Fission.
Warning! Science Content.
Scientists, when they were attempting to create an atomic bomb, were faced with a difficult problem. They wanted to separate the unstable nucleus of an atom, but all previous attempts had proven unsuccessful. When they launched a small proton at the unstable mass, it reacted, much like two North's of a magnet, so that as the proton approached the target, its trajectory shifted. By the time it had reached the nucleus, it was offline. So, Leo Szilard theorized that if they launched a neutron, that it would impact the nucleus, and it did. The neutron stuck to the unstable mass, making it unstable, until it eventually split the nucleus and started a chain reaction, with each new nucleus splitting in an exponential manner, thus creating a nuclear reaction, and giving off a cataclysmic amount of energy.
So how does Nuclear Fission impact LOST? Okay, let's talk only in LOST terms. When a nuclear bomb went off on the show, we called it the incident. The incident is quite really, the splitting of our characters on the show. Our characters were split. Jack's actions did in fact prevent the flight from crashing. The plane landed at LAX. Richard did see them die. Because they all did die in the incident. One half was killed in the explosion, another half was created, by this Casmir effect, and sent back to the new diverted Oceanic flight. They are both Alive and Dead.
They will all retain their memories up until the incident. I'm sure they will all be distraught to see that the Universe will course correct itself appropriately, killing off our beloved Lost characters who died on the island. And they will all return to the Island upon this realization. "They're Coming" Our Dead Losties are coming. Because they are dead. But they are also alive. There is no alternate reality. Just a Casmir effect. The Island is not attached to a timeline, not tethered to our world. So if the Island's time resets, IT DOES NOT EFFECT THE WORLD'S TIME. Nothing will change in our world. Oh, well, yeah, they landed at LAX. And the universe will course correct for that. So, if History happens differently on the Island, well, then, it happens differently. The Island's Time and History seem to be constantly changing anyways. To me, the Island is an extremely unstable mass.
Anyways,
I'll leave it there.
I wonder which Locke will wake up on the plane? The one that hanged himself? That is the question we should be asking.