Talk show host Geoff Metcalf has been harping on the gun business for about three weeks now. There are a lot of people, more than a few on the right, who aren't happy unless they think some Vast Conspiracy is being pulled on them.

As for the military shootdown theory, it fails the same test that so many other such theories fail: there would have to be too damn many people in on it from many different areas and organizations who would all have to keep their mouths shut.

At least, unlike many other mystery plane crash theories, there might be some motive here: protecting the heroic reputation of those on the plane who attacked the hijackers. This is still a bit thin: the passengers did attempt to attack the hijackers, and even if they were subsequently shot down this wouldn't change.