The Malaysia and Trenton postmarks have already been mentioned.
But don't forget that two of the Florida based hijackers rented homes from the wife of one of editors of the Sun tabloid. That coincidence is a bit of a stretch!!
And moreover, a pharmacist in Boca Raton reported Mohammed Atta came desperately seeking Cipro antibiotics, and he had red chemical burned hands, as if he had been washing them in bleach....
Now why would Atta be washing his hands in bleach, and looking for Cipro?
Nah....it must be right wing gun nut militias....