“There was at least one book written about this incident, speculating that it could have been a navy training (inert) missle”
Just one problem with that, “inert” missiles are just that inert. They can’t fly, they don’t go BOOM either.
Why did attention focus on a Test Missile? Initially, it was claimed that there was virtually no explosive residue on the 747 wreckage. In normal practice, missiles being tested or used for training have dummy warheads; inert packages which are the same size and weight of real warheads but which do not explode. In many cases, such practice munitions are recovered and reused. An Associated Press Article on March 10, 1997 reported the following: The report said "compelling testimony" indicated a missile hit the plane on the right side, forward of the wing, passing through the fuselage without exploding. This is consistent with a test missile with a dummy warhead. Of course, it was not known at the time that evidence of explosive residue was even then being concealed from the public, but by that time, the claimed lack of explosive residue had suggested a test missile to most observers, and attention began to focus on the Navy's Cooperative Engagement Capability system, which had been undergoing tests, including live missile firings, along the Atlantic seaboard all that summer. When it was finally revealed that there was explosive residue on the remains of the Boeing 747, the mainstream media tried to explain it away as contamination from a bomb sniffing dog training exercise that ultimately turned out to have taken place on a different aircraft entirely. Had it been true, remnants from a training exercise did not explain a swath of residue ten rows long and three seats wide reaching from an obvious perforation in the forward section trailing back to where the forward section broke away from the rest of the 747.