Who was the first person to say this as if it were a truthhood? IOW, Shermy's question - from where did the idea come?
The idea comes from a document that says Bush was disqualified from flight, in part for not showing up for a physical. These facts were contained in documents "released by Bush." It was wishful thinking that there was a direct written order that Bush ignored.
http://www.cis.net/~coldfeet/grounded.gif <-- See #6.