He sent locke to Aus. He Knew. I wonder Who else he sent there so that they would end up on the Island?

It seems that a lot of people were orchestrated onto the plane:

1) Locke was persuaded by Abbadon
2) Claire was told by the psychic to take a specific flight to LA
3) Sun and Jin were told by a man in a Hawaiin shirt that they had to get on the flight
4) SPECULATION: Was Jack lured to Australia by Christian? Could it be that Chrisitan knew the plane was going to crash and wanted to get back to the island?

On the other hand, there were several people that seemed like they WERENT supposed to be on the flight:

1) Hurley seemingly made the plane against all odds as it seems like he was supposed to miss the flight
2) Sayid was supposed to leave one day earlier but asked to postpone his departure by one day so he could bury his friend

yea I definitely think some people are being manipulated onto the island. Not just flight 815's though. Juliet is an obvious case,Desmond was also lured onto the island by Libby and Mrs. Hawking.
This poses the interesting question of why some people are directed towards the island and some people happen to be there by mistake? There are definitely larger destiny questions in play here for Locke, Claire, and Desmond. Abbadon is definitely a part of a group secretly trying to alter the course of people's lives for a secret agenda, and people like Locke are huge assets for their mission.

What if Christian didn't drink himself to death, but was killed? That would be how they got Jack onto the plane.

There were opposing factions trying to maneuver people onto the plane and to the island.
Since Abaddon hired Frank and Frank says he's working for Widmore, it appears that Abaddon's on Widmore's team.

Abaddon seems to favor a persuasive, manipulative approach, like Ben's. Yet he came right out and suggested the walkabout - Ben would have made Locke think it's his own idea.

Also, Sun wasn't orginally going to take that flight either. She was supposed to be leaving Jin.

Not possible, you mean the "crash" was some sort of pre-planned event? So I'm not supposed to blindly take this show at face value and assume the "crash" was simply a random accident? Like many of the board members, I frankly can't accept that wild leap of imagination. Next thing you'll be telling me Cindy was not just a flight attendant ...
:)

Hahahaha ----- Well she did become indoctrinated by Otherology. Same with the kids...