Eye-witness accounts say there was more than one accomplice in all attacks. <iframe width="560" height="315" src="http://www.youtube.com/embed/wZPS7AdgNgE" frameborder="0" allowfullscreen></iframe>
That guy's a news-anchor on a local fox affiliate. Did you watch it? Those were eye-witness accounts.
There were "eye witness" accounts that missiles hit the twin tower and that explosions were heard. You might want to do some homework about "eye witnesses"