stikpusher
How does one copyright something owned by the taxpayers? The X-1 was funded by NACA, the predecessor for NASA, and owned by the USAF. No matter what name a pilot may paint on an aircraft, it still belongs to the US Government. Unless it is one day sold off. Like the Mercury Capsule Frienship 7 or Apollo Command Module Columbia, or Space Shuttle Enterprise, those are public owned historical names.
The removal of yeager isn't for copyright reasons. It's a matter of likeness rights. These rights are outside of intellectual property law, and are not federal. They fall under the category of 'privacy.' Basically, every person has an exclusive right to the commercial exploitation of their name, image, or likeness. Licenses can be granted, for a price.
Does anyone remember Leonard Nimoy suing paramount over beer ads featuring Spock? I think this happened in the seventies. Paramount and the beer company didn't secure permission from Nimoy to use his likeness in those ads.
I'd guess the kit maker didn't get permission from Yeager. Whether those rights will survive a person's death is another matter, and will vary by State. Although Yeager is still alive, I think that blacking out all refereces to him in the instructions goes too far (insofar as they give historical information). The kit maker could probably have included a generic pilot figure and not referred to it as 'Yeager,' as long as it didn't look like Yeager.
The Glamourous Glennis issue is a more complex matter. The phrase may have been trademarked at one point. Or it may be protected as a likeness right of Yeager's Wife. Or whoever painted the name on the airplane may have copyrighted the artwork. The law on this has changed since 1947, so I don't really know.
As for the design of aircraft and spacecraft, that is protected by copyright (and maybe some patents as well). The copyrights would be owned by the designer, or whomever they sold those rights to. That the taxpayers fit the bill does not matter (although, some believe that the law should be changed in that regard). So North American would have owned the copyrights to the Apollo Command Module, and those are now owned by Boeing as successor.
And finally, in the USA there is no such thing as public ownership.