I saw that documentary as well; very straightforward and convincing. I don't believe this was a missile anymore than the planes that hit the towers were missiles with windows painted on them.
What the best part of the investigation was how the investigators first ruled out what it could have been. What was interesting was that, at first they didn't believer the fuel tank exploded until they recreated the incident.
If the plane had not had waited as long as it did on the runway with the airconditioner below the fuel tank running, it would have never happened. There were several things that contributed to the explosion and had any of these not had occured it would have never happened. The main cause to the accident was just basically bad damn luck.
and I don't have great confidence in the History Channel giving us an unbiased report with so many left-wingers running the station.