lawyers and pens

In article ,
Jim Greenberg wrote:

An let us not forget that PT109 was a patrol boat owned by the US
Navy.

Right. And seems to me that there's been books, movies, TV shows etc
by that name, about those events. The US Navy does not have a
copyright or a trademark on "PT109." Anyone can use it. Ditto "F40"
which is the name of a fighter jet and a Ferrari. Ditto the American
flag, for that matter, and the USS Enterprise.

On the other hand, the gun manufacturer Beretta and auto maker
Chevrolet ended up in court over the use of the name for one of
Chevy's car models. But that was trademark infringement not
copyright- ISTR they settled out of court. Neither side seemed to
have seen fit to sue Robert Blake, but maybe they were just afraid of
him.