[LVB]

To pick on your airport example a bit… all of the times I’ve gotten to enjoy a busted in-seat entertainment system, I’ve found myself staring at a stuck Linux boot process. This goes well beyond the OS.

[fxtentacle]

It's typically Android.

[echoangle]

To clarify: Android is based on Linux.

[pjmlp]

To clarify, the Linux kernel, nothing else from GNU/Linux is exposed as official userspace API.

[Osiris]

The ones I've seen are definitely not Android. But I don't have any data to argue which OS is most common among in flight entertainment systems.