Writing everything 3 times: I believe this is not the case for a car or pacemaker. For the Boeing: 5M/3 = 1.3M lines of code. Still makes no sense.
Obsolete languages: Old language (or Latin) does not bloat the size of your code astronomically.
Usability in specific conditions: does not apply to a car or pacemaker. Yes, for an airplane, it can make the design phase lengthy and difficult but the actual size of the code will not bloat astronomically.
From some of the discussions I have seen on HN, writing safety-critical software is not a question of adding millions of lines of code - to the contrary, safe software must be clean and readable.
Obsolete languages: Old language (or Latin) does not bloat the size of your code astronomically.
Usability in specific conditions: does not apply to a car or pacemaker. Yes, for an airplane, it can make the design phase lengthy and difficult but the actual size of the code will not bloat astronomically.
From some of the discussions I have seen on HN, writing safety-critical software is not a question of adding millions of lines of code - to the contrary, safe software must be clean and readable.