There's some non-DOD avionics floating around that are ADA, I guess because of requirements and regulatory overlaps.
From SpaceX's 2013 Reddit AMA: https://www.reddit.com/r/IAmA/comments/1853ap/we_are_spacex_...
Its an interesting field, but feels hard to get into.
One wonders how much that's contributed to the lengthy delays in software delivery...
Regardless, it seems possible to eventually produce effective software using C++. ;-)