The planes were CGI

As it is told: the second impact looks wrong. The aircraft appears to pass into the façade without slowing or crumpling, a "nose out" shape can be seen emerging from the far wall in one frame sequence, wings vanish rather than shear, and different broadcast angles disagree about details. From this the claim concludes the aircraft were digital composites and the witness accounts were seeded or mistaken.

The no-planes argument was assembled from about 2006 onward, most influentially in the video series September Clues and the forum work around it, drawing on frame-by-frame analysis of compressed broadcast footage. Its central technical claims rest on video artefacts — interlacing, motion blur, and MPEG compression at the moment of highest frame change — that are well understood in video engineering and appear in ordinary footage of fast-moving objects.

The second impact was carried live and simultaneously by multiple independent broadcasters and captured by dozens of amateur cameras from separate positions on the ground, in boats, and in helicopters — footage that surfaced over years afterwards and would all have had to be fabricated consistently in advance. Physical recovery is the harder problem for the claim: a Boeing 767 engine section, landing gear, and fuselage fragments were recovered from the streets and rooftops around the site, one landing gear assembly turning up wedged in an alley in 2013 with its Boeing part number intact. The four aircraft are documented as having departed with crews, passengers and maintenance records; those people are dead, their remains in many cases identified, and calls were made from the cabins. Anyone claiming the aircraft did not exist has to account for the airframes, the manifests and the bodies, and the claim does not attempt to.