It's an entertaining movie, but I don't like to see it referred to as a "documentary". They did a lot of manipulative editing and such to make things seem a lot more dramatic than they actually are.
After seeing the movie/documentary it's really hard to take anything Twin Galaxies says as credible and that link is just a bunch of Billy Mitchell apologists.
Twin Galaxies released a number of statements about misleading/inaccurate things in the movie: http://forums.twingalaxies.com/viewforum.php?f=86
I've heard that the documentary "Chasing Ghosts" is very good, but haven't had a chance to watch it yet.