The intercontinental KLM flight from Sao Paulo to Amsterdam was using a fairly new (05/2007) Boeing 777-300, and it was equipped with something like an 8" wide screen entertainment system, not unlike the one that I saw some months back in a Shanghai Airlines flight.
This time I had the luck to see the Linux based system boot twice. The boot time is horrible (on the order of 4 minutes) and you can see many hardware details. It's using a Geode type CPU and a realmagic GPU, has a natsemi Ethernet chip and the credit card reader is actually a USB HID device.
All over the place they have fairly low-level debug code spit out to the console, this really looks like "it worked on one developer board, ship it to the airline" product. You can see mistakes in shell scripts ("ls: no such file or directory" and similar stuff from init scripts, as well as debug code from their UI applications.
It would really be interesting to get my hands onto an Ethernet link in that in-plane network. Guess one could have quite a bit of fun with that :)
I've taken a series of snapshots throughout the boot process. Will post them once I'm back home and find time to wade through the holiday pics.