I will admit reading the reasons against Linux made me a bit butthurt given how much it has accomplished and the ubiquity of it running on servers that host our services.

However, a (real time operating system) RTOS is distinct from a time-sharing operating system, such as Unix, which manages the sharing of system resources with a scheduler, data buffers, or fixed task prioritization in a multitasking or multiprogramming environment. And a time-sharing kernel is likely not suitable for the demands of real-time feedback that airplanes, especially fighter planes, are under. Admittingly I don't work on the kernels so I might be out of my league talking about it if there are ways to optimize them for RTOS applications. And I also don't work on airplane but hobby learning about them.

In an airplane, the pilots are voting members. If they they are nose diving and tell the airplane to pull up, the airplane will calculate how much of the full range of motion to allow the flaps to "bite" the air so that the plane doesn't desintigrate. This takes into account speed, altitude, air density, load on wings, load on frame, G forces pilots would experience, etc etc.