CVR and FDR have been found, I've read, but nothing has been said yet about what's on them.
I read that some parts were found separated from the main wreck, but hadn't heard it was the tail. Is this verified?
I rather doubt any passenger would have deliberately crashed the aircraft -- more likely that control was lost during the fight with the hijackers. If that resulted in some particularly violent maneuvers, there might have been structural failure which would explain some parts being separated.
What puzzles me about this flight is -- where was it going? According to the reports I've read, it flew due west for an hour before turning back towards Washington. But if the whole point was to have an aircraft with a heavy fuel load, surely flying one hour away from your target and then an hour back makes no sense? Plus the time it would take would negate any benefit of surprise -- and indeed, both the passengers in the aircraft and the air force were by then ready to resist. So: was this flight going somewhere else, towards another target, and then re-routed towards Washington when the flight from Dulles missed the White House and went for the Pentagon instead? But what could that other target have been? Chicago's Sears Tower? But if so, surely hijacking a flight out of ORD would have made more sense for that rather than flying an airplane two hours from EWR?