[Nogbad]

This is clearly European, A4 format.

I wonder what kind of stationary they use in the Middle East?

Here is a wild hypothesis:

The letters were photocopied in the country where the anthrax was made.

[Nogbad]

(And of course, I don't mean the USA)

[The Great Satan]

Or in Germany, where Atta and some of his buddies hung out, or in Prague, where Atta met with his Iraqi control.