Wonderful site. I've never seen anything like this where all the research and documentation is on one page.
I see that you've added a search engine. Very useful. Has it been considered to create a 'visual' version of the 911 Timeline? For an example of what I mean, you can check out an extensive timeline done for PBS:
I think it would be interesting to have an alternate version of the 911 Timeline where you can easily and visually compare the events on all four flights at the same time, minute by minute. (As opposed to a list of text.)
Let me know what your thoughts are.