george wrote:

To 'hack' into a system you have to have an input device like a
keyboard.
A touch screen that allows you to select a film channel, audio channel
or Air phone is scarcely going to go any further than that !
I built networks.
In one building the server ran an Office network, a Student network
and our Tech network.
We could see everything on the other networks.
The students could only see their own network.
The Office staff could only see their own network.

So you have hundreds of passenger devices on the network. Due to a bug, one
or many may malfunction and cause a packet storm, either bringing down the
network or causing unacceptable latency. High latency can cause autopilot
oscillation and loss of control. Oops.

You do NOT put noncritical devices on the same physical network as critical
ones. You just don't. You don't even bridge them together, because
problems on one side of the bridge might crash the bridge itself, affecting
the critical network.