I suspect that the same guy who put a bullet through Moe Greene’s eye did the job on the sound barrier; no one else in The Godfather was anywhere near Edwards Air Force Base, and, let’s face it, the idea of Clemenza in the Bell X-1 rocket plane causes cognitive dissonance on a massive scale; there wouldn’t be enough room in that plane for Clemenza, the gun, or the cannoli. I also have a hard time imagining what the sound barrier could have done to the Corleone family that Michael would feel the need to have the barrier whacked in such a loud and grotesque manner; causing a sonic boom in front of a bunch of eyewitnesses, most of whom work for the government, is not particularly subtle, unless the lack of subtlety is the point of the exercise.
The barrier’s loud demise must have had something to do with the narcotics business, which Don Corleone did not want to get involved with, but this is just speculation on my part; everything I know about the mob I learned from the New York Daily News; but it’s what makes the most sense to me. If the sound barrier got mixed up with dirty cops and the Tattaglia family in the drug trade, then the hit on the barrier may have been simple justice, an example of someone who should have known better becoming involved in a dirty business and then getting what was coming to them. That’s a terrific story, or at least Tom Wolfe thought so, but then again, what do I know?