CNN recently aired a surveillance video from a hotel in Arlington, Virginia of an explosion at the Pentagon that had originally been confiscated by the FBI. According to CNN it shows a explosion "after the crash," but no airplane.
The video was recently made public in response to a lawsuit. The video which was published on YouTube on November 26, 2012, is of poor quality. It may have been shot from the opposite side of the Pentagon, but that's not clear. Because of the poor quality of the footage this probably won't settle the issue of whether or not a plane struck the Pentagon. This is the first I've seen of the video. I don't know the name of the hotel, its location in regards to the Pentagon, or any details about the lawsuit. Those would be important details to know.