He has a mortgage broker that was in the Navy and on a ship off Long Island the night of the incident. The broker said, at the time, the Navy routinely shot inert practice missiles off the coast of Long Island and he said he thinks (knows) it was an inert, radar guided missile that struck the plane.
That was a very popular conspiracy theory (the coverup being the conspiracy), but never had any credibility.
TWA 800 was shot down. It wasn't a US Navy missile that did it.