Yes, but I did it the other way around: I found the aircraft that were using the transponder code, then looked up who they were owned by and what other aircraft they had. That's how I was able to identify potential front companies that don't fit the "XYZ Aviation w/ PO Box in VA" template.

you do understand that flightaware data is crowdsourced, yes? the data format is trivial to fake, and subsequently upload. i am not saying thats the case here, but implicitly trusting user input makes me skeptical about the entire conclusion.

Read my link from the parent comment: https://storify.com/jjwiseman/tracking-fbi-aerial-surveillan...

tldr: I didn't use Flightaware; I observed these aircraft directly using my own receiver, decoding their callsigns and squawk codes, and correlated with FAA records and the company confirmed by the FBI itself to be a front.

But it's true, most of this evidence is still circumstantial. Just because a company with an odd name and no internet presence has the same PO Box as the DOJ doesn't prove it's a front company; but it's pretty suggestive.