do you really suppose replicating the technical requirements of a security-sensitive company of this size in-house would be so easy? I've been doing infrastructure for 25 years and wouldn't want anywhere near this project. but what you will no doubt find is a pool of overconfident volunteers creating exactly the kind of risk outsourcing the problem allowed them to avoid in the first place
The way I understand it is today is when I board on an Airbus I enter an hybrid of a mechanical and digital machine. I understand there is a lot of complex and sensitive software embedded/hosted on that plane that hopefully are not gonna kill me.
So computers are actually core to their business. They probably almost invented things like PLM too.
Nothing Airbus does is easy, this is why there are only about 2 companies like that in the world. This is why I do not see why their hosting have to be outsourced...