Having been out of the Bush administration for quite a few years we can see that the administration was quite corrupt. We knew it then, but it is even more evident now. Given the presidents stance and his fathers history with the Gulf War, I would say it is very possible that 9/11 may have been an inside job. We will likely never know.
First we all have seen the planes crash into the buildings. They were real commercial airplanes and they had passengers on it from all the documents the airports have and the calls made from the plane. The supposedly explosions some people say that was at the bottom were probably things falling from the top to the bottom of the elevator shafts. That would make a lot of smoke and damage things. This could make explosions if it hit the wrong things too.
No, I do not think that it's possible that 9/11 was an inside job, because that would have required way too much coordination. The neocons might not have been upset about 9/11, but I still like to believe that they had way too much of a moral compass to plan something like that on purpose.
For years, conspiracy theories plagued the Oklahoma City bombings because it seemed impossible to believe that one man could wrack so much havoc - but Timothy McVeigh admitted this himself, and also clarified that was the exact reason so many desperate conspiracy theories were formed around the attacks. The 9/11 theories are no different - we simply refuse to believe it was so easy for us to be attacked by a few people.