You have to think it was by design, that they didn't want to go on a flight with the chance of the passengers working against them. If you've got the threat of a bomb or a gun you can hold people at bay. These guys were strong-arming people with box cutters and knives. They wanted the numbers to be on their side.
It really depends on what degree of accuracy you're looking for. If it's just crashing a plane, that takes no more competency than crashing a bus. There is software available. It comes up and it's a 757 flight deck. A friend of mine pulled it up and it's Chicago's O'Hare Airport and there is the Sears Tower Building. You might be able to practice this on your home PC.