Question concerning The Whitehouse & flight 93

Recently i came across a theory that Flight 93 was indeed intended to hit the Whitehouse, but due to an unforeseen 40 minute delay before departure Flight93 needed to now be "taken out". If that was the case and "they" really intended 93 to strike the Whitehouse, who was warned that day and did not show up for work at the Whitehouse for any reason. If people were warned not to fly that day is there any evidence that people were warned not to goto work at the Whitehouse on 9/11 also?

They Knew...

I thought their intended target was capitol hill?

According to NY TIMES.

[edit on 2-6-2007 by grassyknoll7]