1. Jack had a very had time getting on the plane with his father’s coffin. He had to practically break down in front of the Oceanic employee at main terminal to convince her.

2. Charlie switched seats when he went to the first class bathroom to do drugs. The plane started hitting turbulence and he strapped himself into a seat that wasn’t his own.

3. Sun wasn’t supposed to be on the plane. She had planned to escape from Jin and meet a car outside the terminal.

There are so many variables…would a plane crash really be the best way to get specific people to a remote island? For example, a briefcase hit the marshall who was escorting Kate and resulted in his being knocked out and later seriously injured in the crash. What if the case had hit Kate or another would-be survivor? What if someone had decided to use the bathroom shortly before the plane broke apart? What if someone switched seats at the last minute, preferring an aisle to a window or a rear seat to a front? What if someone had forgotten to buckle his seat belt and was sucked out the back of the plane?

Since less than 50 people survived the crash of a plane that probably sat over 200, there would have to be better ways to guarantee the arrival of certain people on the island. Certainly an organization as powerful as Dharma/Hanso could figure out safer ways to make sure they got who they wanted.