Grand Theft Country Home
In a 28-paragraph article that appeared in Newsweek on
  September 24th, only one line pertaining to this incident appeared:

    On Sept. 10, NEWSWEEK has learned, a group of top
     Pentagon officials suddenly cancelled travel plans for the
    next morning, apparently because of security concerns.

 That was it. No other publication covered the story. It appeared on the site, but was removed and is now only available to subscribers, or for a minimal fee of $2.95. [Otherwise, there's a link to a copy of the article below.]
During MSNBC's April 8th, 2004 edition of Hardball with Chris Matthews, 9/11 widow Lorie van Auken reiterated this information, along with mentioning Willie Brown and John Ashcroft's pre-9/11 flight warnings. Upon hearing this information, a stunned Chris Matthews asked, "You're talking about before 9/11 they were warned?" Van Auken confirms with, "Yes. Yes, right," and that was the end of it. You would think that a hard-hitting, "get-to-the-bottom-of-it" talking head like Chris Matthews would want to elaborate on such contradictory information, but there was no other mention in the mainstream press regarding this report.
More on the Pentagon Officials' pre-9/11 warning:
READ      Newsweek: Bush: 'We're At War' [archived by]      
WATCH  MSNBC: 9/11 Widows React To Rice's Testimony