I have not read all the comments, but the United States Air Force has it's own Linux distro called LPS. My guess is that they will use that, or use it as a starting point so they are not starting from scratch. Here is more info:
LPS is designed to serve as a Secure End Node. It can run on on almost any Intel-based computer (PC or Mac). LPS boots only in RAM, creating a pristine, non-persistent, end node. It is capable using Common Access Card (CAC) software for authentication into DoD networks.