Most long-haul aircraft will have inflight entertainment on board. Some will even allow you to stream your own entertainment from a device e.g. tablet, mobile phone etc.
To find out what will be available on your flight and to plan your movie marathons, check on your itinerary to see which aircraft(s) you’re travelling on and then look on your airline’s website. Alternatively, just go prepared by downloading shows to watch on your device or just take a book. Remember them?