All vital systems in any human carrying vehicle (land, sea, and air) should be 100% independent and have absolutely no external connections, such that all interaction must be done with a physical connection and at one single point inside (and under a lock if possible with a real key). This will prevent any external interference through wireless connections. I never believe or trusted any "over the air" updates!
I am tired and frustrated after reading so many "hacking" events since I was a Systems Engineer and a founder of a local ISP, having all the security as my responsibility, too. I changed the password every week, using over 30 character strings and done at the physical site. No one could break it after twenty two years!