Concurrent event: Future 9/11 hijacker/pilot Hani Hanjour re-entered the USA and resumed his English language and commercial pilot training. He was soon joined by future 9/11 hijacker Nawaf Hazmi, a Saudi veteran of the 1990s Afghan and Bosnian conflicts.
I believe this was the first 9/11 reconnaissance mission, prompted by my travel warnings given to Khalid Sheikh Mohammed’s terror cell at the Hayel Saeed Anam Group HQ in September 1997 Yemen.