This sounds ridiculous. Surely it would be very easy to get as many programmers as they wanted for whatever tech they need with the 1 trillion USD that they have.
It would be fine if C++ was the best tool for the job, but I suspect it isn't. If it is not the best tool for the job, then whatever is gained in "programmer availability" is lost in productivity, correctness, reliability or whatever metric a fighter jet's software development is measured against.
Furthermore, this whole IT industry fetish with hiring for a particular programming language is completely misguided. Domain knowledge is usually the bottleneck. I'd expect that to be even more so in flight or sensor software.