This has little to do with government officials. Though very less information is available, I believe the military will use its own personnel or private contractors.
I did not know linux-based RTOS is a security issue for airlines, do tell me why. And ofcourse it will take a toll on the military to maintain the OS. As before this I assume they used enterprise version of windows, so the burden was share between microsoft and the military.
This has little to do with government officials. Though very less information is available, I believe the military will use its own personnel or private contractors.