Blockchain is really for decentralized systems. If you want to keep some data or some simple and small code in a secure,fast and decentralized way, then blockchain can help. Otherwise, for the centralized systems, not as much. I would understand why you wouldn't want one person to have access to all the defense capabilities, but I am not that familiar with the industry.
Sure, you can use a blockchain for storing all kinds of data and code, so you can implement it in the aircraft systems as well. You can create a network that will have it's own blockchain. And then store whatever you want in it and be sure that it is decentralized and therefor doesn't have a single point of failure.
I am not so sure about the benefits of this, since the whole thing is probably based on trust anyway and the blockchain is all about allowing a trustless system and so on.
First, Thank you for your great post. I think this idea really brilliant. I liked that but I'm wondering that How we can use blockchain technology expect keeping datas?
