I did a wide open search of the SSDI database today.

Died on Sept 11 2001. That was the only search criterion.

176,599 people died on Sept 11, 2001, in the USA.

Nothing strange there, it seems to be an average. I tried Sept 11 2002, and 2003 -- all similar figures.

http://stevemorse.org/ssdi/ssdi.html

Using - "Died on Sept 11 2001" as the only search parameter.

Now take your four passenger lists....