Let's begin with this - how far in the future was the action with Jack and Kate in Los Angeles?
It's clear that it's at very least not just a few days or even weeks since Jack and Kate (and whoever else) got off the island. Kate had a lot of make-up on, which did make her look older than her fresh-faced frecked self on the island, and in the flashbacks.
Jack looked a little older, too.
His words to Kate in that great last scene tell us he's been flying around, week after week, on that golden pass - but that could have been for months, or years.
Just on the strength of that scene, I would say the time is less than years and more than months - maybe 15 months?
There was nothing in the Los Angeles environment that gave us a date-stamp - nothing obvious like Barack Obama or Hilary Clinton or Rudy Giuliani or Ron Paul on the television as President. We do know from earlier in the series that the castaways were aware of the Red Sox winning the series (Ben showed Jack a clip) (a baseball event as amazing as the electrical event on the island), so we know that the time on the island is roughly in the present.
A complicating factor is that people seem to age differently on the island - Richard seems to have aged very slowly in comparison to Ben. So, possibly, Jack and Kate have been off the island not that long, but have aged more quickly off the island...
And my last thought, for now ... babies. If Claire got off the island, too, it would be very helpful to see how old her baby is - is Aaron a toddler, or just a few months old....
Whatever the answers to these questions, Lost has broken out of the pod of the island, and made the whole world its centerpiece. The possibilities are intoxicating...
Lost New Questions 2. Who's In the Coffin? ... 3. Who's Waiting for Kate? ... 4. Who Is Naomi's Boss? ... 5. Is Mikhail Immortal? ... 6. What Constitutes Reliable Evidence? ... 7. Are the Flashforwards Desmond's Flashes?
Lost Season 3 Finale ... Flashforwards
Lost: Keys to What's Really Going On
And see also Lost's Back Full Paradoxical Blast: Season 4 Episode 1
The Plot to Save Socrates
"a Da Vinci-esque thriller" - New York Daily News
"Sierra Waters is sexy as hell" - curled up with a good book