So...I keep finding myself wondering about two things over and over again...
First off, the 'Flash Sideways' was a sort of 'purgatory'. All of its (spiritual) inhabitants either died on the island, spent substantial time on the island, or were directly connected to somebody in one of those catagories. It is clear from Jacks dads comment (and a few other hints here and there in retrospect) that the dead lostaways and other dead folks of the island (with a few others) effectively created the Flash Sideways realm, which, I'm fairly sure probably didn't amount to much more than just LA, and probably just parts of that, along with a few airplane interiors ('thoughtform' in new age magical lingo). We *know* Hurley was talking to the dead denizens of the island, mostly lostaways but also other folks (like Richards wife). I keep getting this vision of him talking to the spirits on the island during his tenure as Guardian, saying:
"Dudes, I'm changing the rules. I'm going to sorta set it up so you can leave...the deal is, you try real hard to imagine what your life would have been like if you'd never come to the island...oh...and that life has to be in LA..."
I also find myself wondering what happened to the people who died in the Flash Sideways realm. Did they once again find themselves aimless island spirits?
I also noticed that there seemed to be different 'groups' within the flash sideways realm. We had the interconnecting lostaways. We had the criminal group (mostly killed in the resteraunt). We also had the 'Widmore' and possibly 'Dharma' groups started thinking about this when I saw Chang giving his intro speech at the concert.
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Somebody else here already touched upon the other bit I find myself wondering about. That Aljira flight took off from LA with the Oceanic Six, Lapetus, flight crew, Jacobs bodyguards, and a few other stray sorts. It lands on the island, which means it is presumed crashed. Usual procedure from the news would be to spend a few days searching for it, then give up. Plane spends something like a week or ten days on the island and then takes off - but only two of the original two dozen or so people that were on that flight are onboard: instead we got two more Oceanic survivors (Sawyer and Claire, both dead according to the 'Oceanic 6'), Miles (who was on neither the Oceanic flight nor the Aljira flight), and Richard, an unknown. So to land that plane anywhere civilized without facing serious prison time, the people on board would have to A) explain what happened to the two dozen missing people; and B) account for the people not on the original manifest. Yes, Sawyer, Miles, Claire, and Richard might claim to be people off the manifest...but that still leaves a lot of people unaccounted for, plus it still doesn't account for that plane being back in the air a week or two after it supposedly crashed. Best I could come up with here is this bunch would have to crash the plane a second time, with the new official story being that Kate and Lapedus were the only Aljira survivors, and the rest were never on the plane - and they'd have to ditch it in the ocean so it'd sink and that wreckage not examinable.