Hacking into cars via wireless

The excellent RISKS DIGEST has a better analysis (with some gentle debunking) of car firmware hackability than I've seen elsewhere, including this lagniappe:
There is a wonderful cartoon from the German computer magazine *c't* pinned to my group's noticeboard. A passenger is sitting in an airliner using his laptop, and on the screen appears:

Bluetooth: new device found: Airbus A310