Airplane software is, without a doubt, one of the most complex system that you will see nowadays. 100's of people's lives depends on the proper functioning of an airplane. And, everything in the airplane is controlled by software systems.
Although NASA's spacecrafts, like InSight, gets a lot of attention, airplane softwares are just as complicated as that of NASA's spacecraft. Building an avionics system takes a lot of time, money and skill. And, your life depends on the proper functioning of airplane and airplane software.
So, how does it work?