To be more accurate, a hacker claims that airplanes WILL BE vulnerable. I'm a little confused about how he claims to know this. Correct me if I'm wrong, but he

To be more accurate, a hacker claims that airplanes WILL BE vulnerable. I'm a little confused about how he claims to know this. Correct me if I'm wrong, but he hasn't seen the system in development or explored its security vulnerabilities. >"The problem with this is that the signals they are using are unencrypted and unauthenticated." How do we know that? The final product doesn't even exist yet.