Plex needs to team up with airlines to run the in-flight movie systems, it's the perfect use for a local media server. And the Plex apps are way better and less crashy than whatever crap the airlines are buying.
They typically either use a satellite or a local media server. The local server can be down a lot but I suspect there are a lot of parties to share blame across there, not just the media system vendor.
Plex might not want the bad press ;-)