They now work on radar systems at Thales Group. I've read that it's also widely used in aviation, e.g. at Boeing[1] or Airbus. As for general development, from my (albeit limited) experience the type system is a bit heavier than I'd like. It's certainly a great help for highly reliable systems, but most applications probably don't need such a strict language.
[1] "The Boeing 777 Flies on 99.9% Ada" http://archive.adaic.com/projects/atwork/boeing.html
[2] "Airbus chooses AdaCore for autonomous aircraft software testing" https://www.aerospacetestinginternational.com/news/software/...
https://github.com/JeremyGrosser?tab=repositories&q=&type=so...
It's just so damn comfortable to use that I often have a hard time using other languages now. I think writing down what things mean in the type system helps catch any issues in my approach before I get too far with it. Being able to easily but powerfully write down what things mean in my programs is amazing. I don't need to worry about unloading some part of the program from my head, because everything I need to remember is written down - and enforced by the compiler.
Once I got over feeling paranoid when my programs just worked after they compiled, I found I could actually relax quite a lot while programming. There's just so much stuff I no longer need to be constantly watching out for. It's great.