The Journal of 9/11 Studies has published a brief but important letter: Update on Why Did the World’s Most Advanced Electronics Warfare Plane Circle Over The White House on 9/11? By Mark H. Gaffney

In his Letter, Mark Gaffney notes "CNN has now confirmed the basic facts regarding the USAF E-4B fly over of the White House on 9/11." Furthermore, Mark has updated his detailed paper on this subject, which appears in the July volume of the Journal of 9/11 Studies. His full letter is below.

Mark's research raises compelling questions IMO regarding the presence of this sophisticated USAF electronics jet over the White House/Pentagon area about the time the Pentagon was hit. Of course, the military denies its presence -- but with the clear and substantiated evidence gathered by Gaffney, this denial is tantamount to cover-up. I think this is a very important line of inquiry... one which should be pursued by Congress/other investigations; it would no doubt be important (for example) in an impeachment proceeding.
Reading of Mark's updated paper is also highly recommended, here: http://journalof911studies.com/volume/200704/Gaffney_911Mystery%20Plane.pdf