There are multiple eye witnesses to a plane crashing into the pentagon on 9/11,

Operation Mockingbird can plant "eye witnesses" anywhere they want in the fake news media.

the flight was tracked by Air Traffic Control as out of contact with them and off track headed to Washington DC and coming down at the Pentagon,

Actually, no, it was not "tracked" the entire way. There was a point when the flight was "missing" and later re-appeared. Do not have link because these kinds of stories magically disappeared from the internet over the past 20 years.

One theory is that parts of 9/11 were copying Operation Northwoods, where the plan (approved by the Joint Chiefs of Staff, but refused by JFK) was to replace real planes with drone copies. In this case, replaced with a missile.

there was an explosion at the Pentagon

Missiles and pre-planted explosives go BOOM, too. And there was no plane apparent on the ONLY video frames EVER released. If the govt's story is true, why then HIDE all the available video footage?

after witnesses saw a plane flying very low overhead

Operation Mockingbird.

and clipping a street lamp before it hit the Pentagon,

Can't stage a crime scene without something that looks good.

Where are all the plane parts at the Pentagon? Where are the 6-ton titanium engines? Just went POOF? When has that ever happened in the history of the world (other than 9/11)? Where is the tail section? Where are the wings?

the passengers from that flight are all dead.

Probably. But we don't know how they died.

You have a news reporter who in the heat of reporting what happened mistakenly said a missile hit the Pentagon.

Rumsfeld said it, too. The word "mistakenly" is conjecture, NOT evidence.

There were not witnesses to that. If you want to find the truth, don't disregard every witness and piece of evidence to it.

Agreed. Where IS the pieces of evidence that a plane crashed at the Pentagon? Where ARE the pieces of a Boeing 757?