http://abc.go.com/primetime/lost/index?pn=mb&cat=33026&tid=640377&tsn=1SUMMARY: In short, the bomb goes off in 1977, the Swan hatch is never completed. However, Flight 815 does not go to LA, but instead lands on the island as it was always intended to do. The theme for Season 6 will be why the O6 were brought to the island, and the coming war.
DETAILS: So we know the island has a way of course correcting itself. We also saw in season one a strong hint that major characters were PLACED on the plane (e.g., Claire and Sawyer each given tickets, Kate placed on the plane against her will, Jack absolutely must take this exact flight back as it is the last one that will get his dad's body back to LA in time for the funeral). We also heard the comment in Season two that Jack was not on Jacobs list (in the context of he was not on the list of people intended to be on flight 815).
In season 4 Lapidus tells us he was supposed to be flying flight 815. In season 5, we are shown flight 316 make a landing on a landing strip that was built on or before 2004/2005 (with Kate, Sawyer, and 4 Others chopping rocks to either finish the new runway, or simply maintain the existing runway, which would be necessary given that is made only of rocks and gravel, not concrete).
Since season 2, I have advocated that Flight 815 was coming in for a landing to the island, but Desmond screwed things up by failing to enter the numbers, thereby causing the low-flying plane to break apart and crash (much longer tangent post made in season 2 and 3 why the plane was landing).
Now to season 5 ending....Season 5 does in fact end with the bomb going off, leaving us thinking (as was planted in our heads in Episode 515 "Follow the Leader") that flight 815 will continue on to LA and land. HOWEVER, this assumes the pilot of 815 was planning to fly to LA. However, if the pilot was intending to land the plane on the island, then after the hydogen bomb explodes in 1977, Desmond will in fact never fail to turn the key because the Swan Station was never finished/built, and Flight 815 will (course corrected) fly into the island for a landing as was planned all along.
And finally, Season Six begins with a plane coming in for a seamless landing (possily flown by Lapidus, since I believe he has flown this route to the island many times*), and as the opening scene pans back from the inside of the plane where Jack and Kate and Sawyer, et al are riding, we see an island with a rough runway and Others (perhaps even Jacob) outside waiting to greet those selected to come to the island.
Side note: Some have said there is not enough time in one season to cover what seems to amount to a reset of the entire show. HOWEVER, in season 5 when Desmond goes looking for Faraday, the janitor protector at Oxford mentions that Faraday's experiment involved sending rats memories into the future through the radiation. If a hydrogen bomb goes off, this is exactly how this will be solved for the show continuity - It will not involve a reset, but the O6 will carry their memories with them as Faraday's mice experiments proved could happen. We have already seen an example of how a historical change in time suddenly appears in the future of those impacted as sudden memories - When Faraday bangs on the Swan Station door and Desmond comes out, as the sky flashes, Desmond sees it too and not just Faraday (as was always the case that only the time travelers noticed the sky flash). Suddenly the next scene Desmond awakes in 2007 suddenly with a NEW memory - Not a dream but a memory. Thus the events in 1977 will suddenly be in the heads of the O6 as memories.
Thoughts?
Thought his theory was pretty interesting and a great direction for the show to head for the final season. It also goes with the tease "Destiny Found".



















