Oi Vey!
I didn't see anything hit the Pentagon either... but I was 1,800 miles away at the time. But you will also have folks that can't see the 800 lb gorilla standing right in front of them... trust me, I've put folks in situations quite close to that in shows and it is truly amazing what one can do and they do not register the fact that it happens right in front of them... that includes people with "trained" eyes... Let me give you an example;
I was at Caesar's Palace about a decade back, with my partners from Creative Illusions.. .we design and build magic for the big guys and in this particular case, the big guy on stage was David Copperfield. I'll not say which routine he was doing but basically David vanishes on stage and ends up in the audience... a classic bit of business, right?
So there we are sitting in the Producer's booth, David makes his "secret" run past our table, pats me on the knee as he goes past as a kind of pun, and yet my two partners were dumbfounded when it came to his appearance in the audience.. .the did not see him walk directly in front of them.
Blackstone Sr. used to make an Elephant vanish on stage by producing a burro on the opposite side of the stage... the audience would see him doing the production AFTER seeing the elephant make it's entrance... as they watched the elephant would be walked right back into the wings and on cue, smoke pots would go off and voila! No more elephant!
I could list dozens of scenarios on and off stage when it comes to people not seeing things right in front of them as well as "psychological" or "emotional" censoring. In simple terms, people that witness something horrific unconsciously delete that memory from their recollection. This is very common in the harder PTSD cases in the Military as well as with children that have been brutalized or seen their parents tortured/murdered. I happen to be just such a person; a large amount of my "childhood" has been blocked out because of how abusive my father was, it's quite common with people in my age group and for similar reasons.
So we have more than a few reasons as to how and why people didn't see the Pentagon collision. The issue of wreckage is also explainable, in that the plane actually WENT INTO THE BUILDING'S FIRST 3+ RINGS... most all of the parts to the aircraft and its passengers went inside the building and given the speed vs. mass factor, I'm certain most of it "powdered" on impact... leaving very small indiscernible parts... but then the large engine housings found in a couple of offices would probably make most, especially the news camera team shooting them, reason to believe a plane crashed into the building.
While I love the fantasy tied to some of the various conspiracy theories the only major topic I have some empathy with is the Grail Lore and church related cover-ups. I'm not speaking of the whole Illuminati horse pucky as its been made, but the truth behind church treachery, cover-ups, suppression and acts of genocide I very much believe in and that would include the whole Jesus was a Daddy theory... I've had that belief for a very long time, well before the DiVinci silliness.