I work in one of those huge office buildings in STL, and believe me, they're being fully utilized. AT&T still has a huge presence here.

I don't have any aircraft design qualifications, but I do have enough common sense (and a Cisco certification, but common sense is all you really need) to know that no firewall is fool-proof, and given enough time and effort, someone possibly could penetrate it. With the lives of a few hundred people on the plane, and possibly thousands more on the ground at stake, why not just be safe than sorry and have the 2 networks completely separate and independent of each other.

And it may not even take a hacker. Maybe some innocent, computer illiterate person is just browsing the web, and the system doesn't like some website and crashes the entire network, and the pilots lose control of the plane? If I'm going to die in a plane crash, I'd rather it be from something a bit more serious than grandma checking her e-mail.

horde!