Currently, I don't believe Osama had anything to do with 911. I think this conversation is out to make their story credible. If you watch the German TV show (it was linked here) that openly discussed some of the scapegoats that backed out of whatever the original plan was. If Hijackers were on those planes like the Govt. says the videos would have been plastered all over the news media. I think this is similar to the 7/7 bombings, there was a plan (IMHO) to get muslim looking men on the planes but they were getting on for reasons other then to take it over. The 7/7 bombers were part of some type of drill and I believe they thought they were carrying something other then a bomb.