But I can't afford any of those things, so it's a highly theoretical issue (to me).
So, deal with the theory. A tank is simply a vehicle, and the laws that apply are motor vehicle statutes. The machine guns and cannon are arms, and, like a howitzer, current law covers them, and specifically in the case of cannons, the gun its self is not prohibited (yes, even fully functional). Each round of explosive ammunition IS covered under law, restricted, registered and taxed as destructive devices. The cannon itself, I believe, is not.
The F-16 is a bit of a unique case, since you mentioned that aircraft specifically by name. The aircraft itself isn't specifically prohibited from private ownership, but there aren't any, (that I've ever heard of) in private hands, because none have ever, yet, been released for public sale.
There are people who own tanks, and cannons, all 100% legally. But not the current in service models, as they haven't been released for public sale, There are people who privately own jet fighter aircraft (unarmed, as the guns are regulated separately). There are some privately owned F-86 Sabre Jets, the famed Korean war Mig Killer. They are obsolete as military aircraft, and some countries have sold some to US citizens.
Its not about what you or I can afford, its about what the govt restricts or prohibits legal private ownership of.
Back to the Supreme court ruling on "taking guns from Domestic abusers"...they didn't rule on that. Despite the fact that the popular media is claiming that, and putting various "law professors" and other "experts" that say that in their broadcasts and on U Tube, that's not what the Supreme Court "upheld".
What they ruled on was whether or not it was Constitutional for a judge to put a firearm prohibition in a restraining order. NOT the law that prohibits convicted domestic abusers from possessing arms, but what was Constitutionally permissible in a court issued restraining order.
The Court upheld the practice, WHEN the issuing judge has sufficient evidence to justify it. This is NOT what the overwhelming majority of "public opinion" commentators are saying or talking about.
Once again, SCOTUS rules on a narrow point of law, and the public is deliberately misinformed about what it is, and what it means.
Sadly, its not even remotely a new thing, or even a gun law thing. They do it with everything....