Actor James Wood reported the 9/11 hijackers while they were on a test run!

The 9/11 hijackers were trained to fly airplanes in the US. They went to flight school here, and it turns out, they also did a test run of the 9/11 attacks here. Actor James Woods encountered some of these men a month before the actual attacks.

Woods was taking a flight from Boston to LA, and the only other people in first class with him were four men "of Middle Eastern appearance." The men were acting strangely throughout the duration of the flight--they didn't eat or drink, they didn't read, and the only time they spoke, it was in hushed tones.

Woods reported his observations to the flight attendant but said that she "shrugged it off." When he arrived in LA, he reported his observations to authorities there too. Again, they didn't seem too concerned. After the attacks took place, Woods contacted the FBI and told them about his experience.

(Source)