What Happened With Air Defense on 9/11?

The 9/11 Commission has come forth with some answers to what I've always considered one of the most important questions re: 9/11: what the hell happened to our vaunted, very expensive air defense?

The answer, as detailed in this thorough account (as printed in the L.A. Times, reg. req.) of reactions to each of the four hijacked flights, is apparently: air traffic control and the Federal Aviation Administration weren't very scupulous about informing the military that anything was going wrong.