Re: I was thinking this was bogus
"These systems are fully air-gapped and there are no wireless links and no way to access these things without being in the cockpit or other engineering compartments ...."
Don't you mean that you *hope* they are airgapped.
In fact it seems quite likely that important systems are not truly airgapped at all. Hopefully they don't have a wifi or bluetooth interface, but the air-ground radio systems provide radio access, and he claims it is unencrypted.
These are likely directly connected to flight information display systems and/or navigation, and they are probably connected to other systems.
So this probably breaks the air gap, and reduces it to " well you can't push data in one hole and make it come out another one the designer didn't intend". History hasn't been too kind about that one.
Now the in-flight entertainment system displays the current position, and airspeed. Unless they have put a separate GPS antenna + pitot tube on just for this, it probably has a data connection to the navigation system.
So (about 2008) I got on a plane in BKK, and plugged my phone into the USB socket on the inflight tv thing (the type that lets you play your own photos and mp3s), as soon as I got seated (ie about an hour before we took off). When they started up the in-flight entertainment, well bugger me if it doesn't start to boot linux - I have a linux boot on the phones USB mass storage for an industrial tool, and the in-flight entertainment is booting off it, and happily scrolling the boot log. So next time I flew with them I brought a little mini usb keyboard and hub, and could merrily run linux console on the screen.
Actually it didn't work out so well, because that time I was on a 15hour flight, and it wouldn't actually reboot back into the entertainment system.
The linux console is more boring than even the worst movie (ok 50% of movies)
So hopefullly this guy hasn't found out how to do it.