My good friend Iranga, had taken this photo (on his way to SL from UK) of the Linux kernel booting on the on-flight personal entertainment system of a First Choice Airline.
So I guess, First Choice has chosen GNU/Linux as its first choice! Iranga told me that once the kernel booted it loaded a kiosk like interface.
But if the airline itself ran on the Linux kernel? or any other commmon OS? Reminds me of this joke...
http://www.webaugur.com/bibliotheca/field_stock/os-airlines.html