In the "no plane timeline" the author of oilempire.us examines the claim that there was a conspiracy attached to the September 11, 2001 attack because it seems there was no plane that hit the Pentagon. There's some curious aspects to the Pentagon attack, that's for sure, but I doubt those curiousities indicate that there was no airplane.
These people want us to believe that someone arranged for an airliner to be taken surreptitiously to Cleveland and that instead a missile was fired at the Pentagon.
It is curious that the early pictures of the Pentagon damage show only a small hole in the outer wall. How can a Boeing 757 leave a small hole in a building?
The root of this story comes from French political activist Thierry Meyssan who constructs this theory and it spreads from there. The timeline linked above attempts to show that the spread of this story is based on some misinterpretation of the evidence.
For me the key point countering that theory is ... what happened to the people on that airplane? If they were flown to Cleveland and instead a missile was shot at the Pentagon, then why didn't the people on that airplane return to their families? Were they instead taken elsewhere and killed separately? If so, then why?
This theory seems to violate Occam's Razor by introducing extra complication.