This article discusses the statements of two important persons with regard of foreknowledge about the unfolding crisis.

In the 911-commission reports stands ...

"Shortly after the second attack in New York, a senior Secret Service agent charged with coordinating the President’s movements established an open line with his counterpart at the FAA,who soon told him that there were more planes unaccounted for—possibly hijacked— in addition to the two that had already crashed."
http://web.archive.org/web/20041020144854/http://www.decloah.com/mirrors...

This account is based on the statement of the senior Secret Service agent, Nelson Garabino. He says his FAA-counterpart, Terry van Steenbergen, said (a few minutes after the second plane crash) to him, that ...

"... there were 4 planes believed to be hijacked and 2 outstanding believed to be travelling to D.C"
http://www.scribd.com/doc/14353654/DH-B5-secret-service-requests-fdr-ent...

Mister van Steenbergen describes the moments ...

"On 9/11