This is already a very juicy bit of information. I'm surprised this hasn't gotten more coverage already. The "Let's roll" narrative was pushed everywhere.

Possible explanations:

1. The plane was shot down out of necessity because the military caught on that the planes were being used as missiles on populated targets. The "Let's roll" narrative was fabricated to soften the blow of the tragedy, increase patriotic fervor, and avoid a painful conversation about our military shooting down American citizens.

2. Even more disturbing is the possibility that the "Let's roll" narrative was real, but the military was ordered to shoot the plane down because of the possibility that the passengers might recover and land the plane. If some part of the government was involved with the hijackers prior to 9/11, they would not want them to survive and face questions from investigators.

Hopefully the Layer 3-5 documents will shed some more light on this!