I have to agree that my first reaction was similar to Deman's. Here we have an elaborate conspiracy that threatens being found out because... they didn't make any effort to disguise the planes? I have more faith in my government's ability to lie. Then again, they have been exposed more than once: the start of the Spanish-American war, the start of Vietnam (Gulf of Tonkin Resolution), hell, the whole WMD thing might even qualify.
Anyway, I found the most convincing part to be the investigation of the Pentagon crash. It can't be denied that it didn't make ANY sense for the hole to be that thin, or for so little wreckage to be found. Forget the eye-witness testimony, because obviously that's so varied it's stupid. Just look at the evidence. Look at that engine that could never have come from the kind of plane they described. Look at how far the plane's fuselage supposedly got without even leaving a remnant. Why WOULD they only release five frames of the ONLY footage they have of the plane, when it would dispel any doubts if it was in fact the plane they say it was?
Plane's that big make bigger impacts. And they don't just disappear. That stuff about that section of the Pentagon being the only part of the Pentagon reinforced against explosions and such... I dunno. It's shifty stuff.
Obviously, the people that were on these flights are not here anymore. Nobody is saying your dad's friend is really alive or something. On the contrary, the implication is that the people who were on these flights may have had something entirely different happen to them.
As for the towers, I think all of those reports of the "explosions" just before the collapse were pretty interesting. People are unreliable, but... well, I dunno anymore.
And Fire, please don't attempt to imply that bananas have structural integrity, and can thus be compared to a 100 story skyscraper. You'll only sound very silly. As well, C-130s don't just fly routine patrols around DC just in case of the need for a "rescue mission"...that's absurd.