Nonono, you don't base any mission critical systems on Windows 3.1. Not the year it was released, never in a lifetime, and definetely not today.
Thank you!
My point exactly. If someone wants to run his shop/business on MS-Dos, by all means go ahead. Many still do, and there's nothing wrong with it (your tax accountant might disagree).
But a mission-critical system for handling hundreds of aircraft? That's almost criminal in my book.