Most aerospace stuff is. The thing is, they have reams of very specific rules about how it's coded, how to verify that code, and how to verify the compiler of that code, and how to verify the code output from that compiler. It's not an easy process to replace, but its proven reliable just by all the commercial planes flying every day without falling out of the sky.
In theory, something like Rust could do the job instead, but they'd still have to verify the entire chain. Rust is for the rest of us to get something half as reliable as that while also being able to write more than two lines of code per day.
I actually met a programmer who worked on military jets. According to her, Ada is only used anymore for the older jets that were already programmed in it, and she worked in C++.
I wouldn't trust USB flash drives with anything long term. Best archival method would be to print something out (perhaps an encrypted message in a QR code), have it put away somewhere secure, and use that for a key to unlocking everything else.
Which also gives away some gaps in the author's knowledge.
Perl wasn't following the PCRE standard. It was the PCRE standard. Everything else was following it. Usually with some piece missing--far more implementations should have the /x modifier.
The Perl 6 design process didn't throw it away after 30 years. It threw it away with less than 10 years. There was already widespread knowledge that Perl had gone beyond "regular expressions", and IIRC, that was even before it had implemented recursive expressions. Perl 6 would be "patterns", and they would be good enough to be used as a full grammar. The language itself could be parsed in it, and Raku sometimes is, depending on the implementation.
It doesn't go the speed of light in copper, either. In fact, that study has a nice table on page 5. Looks like other than thick coax, fiber is a bit faster than most copper options.