It is not clear how the shootdown order was communicated within NORAD. But we know that at 10:31, General Larry Arnold instructed his staff to broadcast the following over a NORAD instant messaging system: "10:31 Vice president has cleared to us to intercept tracks of interest and shoot them down if they do not respond per [General Arnold]."²²⁹

In upstate New York, NEADS personnel first learned of the shootdown order from this message:

Floor Leadership: You need to read this.. . .The Region Commander has declared that we can shoot down aircraft that do not respond to our direction. Copy that?

Controllers: Copy that, sir.

Floor Leadership: So if you're trying to divert somebody and he won't divert-

Controllers: DO [Director of Operations] is saying no.

Floor Leadership: No? It came over the chat.. . .You got a conflict on that direction?

Controllers: Right now no, but-

Floor Leadership: Okay? Okay, you read that from the Vice President, right? Vice President has cleared. Vice President has cleared us to intercept traffic and shoot them down if they do not respond per [General Arnold].²³⁰

In interviews with us, NEADS personnel expressed considerable confusion over the nature and effect of the order.

The NEADS commander told us he did not pass along the order because he was unaware of its ramifications. Both the mission commander and the senior weapons director indicated they did not pass the order to the fighters circling Washington and New York because they were unsure how the pilots would, or should, proceed with this guidance. In short, while leaders in Washington believed that the fighters above them had been instructed to "take out" hostile aircraft, the only orders actually conveyed to the pilots were to "ID type and tail."²³¹

In most cases, the chain of command authorizing the use of force runs from the president to the secretary of defense and from the secretary to the combatant commander. The President apparently spoke to Secretary Rumsfeld for the first time that morning shortly after 10:00. No one can recall the content of this conversation, but it was a brief call in which the subject of shootdown authority was not discussed.²³²