I think the main distinction of patent trolls is that they don't attempt to develop their product, and for related reasons generally don't do any substantive research to acquire their patents

Not sure the Wright brothers can be accused of those particular issues

The definition of a patent troll is hard. While your definition is currently the common definition, I believe we have to look how we reached that definition.

The first question we have to ask is: How do we not like patents to be used?

> its impact on the state of American aviation was indisputably negative.

We don't want patents to be used in a way that deters further research and advancements in that field.

Can we determine if a way of use will do that in the future? Unfortunately, as we can't see into the future, we don't know.

So we use the next best thing: We try to find patterns that strongly suggest that someone is abusing a patent.

And the pattern that we found is: People who just buy patents (sometimes for just $1) and don't produce their own are more likely to abuse patents. And that's how we came to today's definition.

But for the past, we can answer the second question. And we should use this as definition if possible.

It’s rare for a patent (or airplane) to change hands for literally $1.

It’s common for them to change hands for “$1 plus other valuable consideration” to mask the true price. Sometimes that “OVC” might be 999,999 other dollars for example.

That may be the wrong question to ask. The question we might want to ask: do patents incentivize innovations or not? In what way they do and in what they don't.

>I'd include some restrictions on the patent itself, and how novel it was.

I agree in principle, but back then, the granting of a patent was a sort of de-facto legal recognition of the novelty. (Whereas today, it's just recognition that you can fill out the forms correctly.)

There wasn't really the need to litigate that aspect of a case. If the patent was issued, it was legally presumed to be novel.

Which is a main part of the reason why patent trolling has gotten worse: lack of legal certainty that any particular patent is valid.

> back then, the granting of a patent was a sort of de-facto legal recognition of the novelty.

There is still a de jure presumption of validity for an issued patent, but it only means that when a patentee sues an alleged infringer, the patentee doesn’t have to first prove the patent is valid. An accused infringer will usually challenge the validity of the patent, it just won’t happen at the earliest stage of the trial.

> how novel it was.

There are no degrees of novelty. An invention is ether novel (new, never been done before) or it’s not.

Of course there's degrees of novelty. How could there not be?

In patent law, novelty only means new (never done before). Patent novelty has nothing to do with the cleverness, inventiveness, or importance of an invention.

A patent must also be non-obvious, which is where many of the other inventive characteristics fall.