Not quite... It is the Studios/distributors who put the watermark on the content. In case the movie gets pirated, this allows us to narrow down where it was pirated/leaked. Content is delivered quite early (obviously before it's loaded on the AVOD systems) and airlines - or their suppliers - have stringent obligations on how it must be handled; they would be held responsible if a pirated version of a movie was found online and it had their watermark on.