Nope, not CGI; it's actually one of a stereo pair that I shot with two Nikon L12s wired together, if you'd like to see it in 3D. But no, the shot is from the passenger side window looking toward the front-right quarter, not behind. This witness would have seen the approach through his windshield, but could have easily seen the flyover out the right window, if that had happened.
Excuse me, but we're talking about a guy who saw the plane "diving toward the building" and then saw the fireball. For your "illusion" to work even for people to the west, the plane would need to pass very, very close over the roof. It's ridiculous to assert that anyone -- even those who didn't see the plane before impact but looked over when they saw the fireball -- would have mistaken that for a plane on a normal National flight path.
He, himself, says that he saw the plane "hit the building" because he saw it "diving toward the building," too low to miss it or to pull up, and then saw the fireball, and then he didn't see the plane flying over the roof! How else would you describe that scene? Look at the picture again and try to imagine what he saw, from a position about perpendicular to the flight path. I think it's perfectly reasonable for him to say he saw the plane "hit the building" even if he didn't have a direct view of the actual impact wall. You might say that his estimate of the plane's altitude may have been off, so that's just a "logical conclusion" rather than a direct observation, but the ONLY other possibility is that the plane simply disappeared, Lyte! Do you claim that as a reasonable possibility?