All of the strongest SWEs at Boeing got sucked away to FAANG in Seattle for 2-3x TC. Check them out on LinkedIn... there's been a steady brain drain to those companies for many years. Some were even early Amazon employees. It's crazy to realize Boeing had "big data" at the time when Amazon was still a startup.
They've been using multiple languages for a long time and were, as far as I can find, never exclusively using Ada. At least with the 787 the language choices we (subcontractor) had were Ada, C, and C++.