I wouldn't be at all surprised if Widmore, Paik, 'Jacob', etc all conspired to get these people on the same plane and 'crash' them on the island, as everyone above seems to believe is possible. It would give the Others many more guinea pigs to test with, at the very least.

But that makes me wonder how they actually got the plane to crash. Wasn't it Desmond's doing when he refused to push the button after killing Kelvin? I doubt Des is involved with the conspiracy at all. And didn't the Others seem surprised when the plane crashed and Ben sent the two guys in as spies? If it were all planned in advance, wouldn't Ben know about it? Maybe not, but I still don't understand how they could've gotten the plane to crash without using Des . . . unless that wasn't what brought the plane down?!?