They're not wrong, Linux does NOT have the safety culture that air safety needs, this is partly due to Red Hat "innovations", partly due to the fact it was never created to handle mission critical needs from the ground up.
For the love of God/s keep #RTOS
https://www.phoronix.com/news/Linux-On-Airplanes-Challenges
Most people the Linux Fandom in comments don't understand OS's outside of Desktop usage.