Depends what "navy" you refer to. If you refer to the american, then they're like most of the other US armed forces (and military in other nato countries for that matter) and are increasingly contracting out development work (or expect it built into the specific hardware) to public companies. Public companies that don't have an interest in "magic tools" or "unfamiliar development tools" they can't find developers for.

I've done work for companies that have military contracts, and I've never even seen anything written in ada.