Earlier quoted context omitted.
Note, however, that this doesn't mean that he would have gotten away with it if he'd cooperated. It means that the federal prosecutor decided that the act of obstruction would be easier to prove, since the intentional nature of those acts is much more self-evident.
Is there a law that says you can't intentionally crash a plane? Honest question. There isn't a law that prevents you from intentionally crashing other vehicles. Just around property damage and endangering other people.
You can probably do whatever you want with your private vehicle on your private land. But on public roads you need a license to operate, and you must operate the vehicle in certain prescribed ways.
Similarly you can probably do whatever you want with your private air vehicle while it sits on your private land, but when you are operating in public air space then you must operate in the ways prescribed by your pilot license.