Alaska Airlines is currently rolling out their Alaska Beyond™ Entertainment service on their 737 planes. This service will allow you to watch TV shows and premium movies on your own device. Supported are so far Apple iOS, Android and Laptops (via Browser plugin). To find out if the service is available at your next flight. listen to the cabin crew announcements or check for a card in your seatback.
I would recommend you to download the Gogo video player app before you fly, but according to the news announcement from Alaska Airlines it will also be available inflight. This planes will also have Gogo Wi-Fi onboard and you can buy a pass for the flight. If you are an American Express customer you might be lucky and get a free Boingo WiFi subscription.
However if you don’t have a device, which I would say is nowadays very unlikely, you can rent devices on longer flights. The rent depends on the length of the flight and starts at 8$.
All the content is stored at a server aboard the airplane and gets updated regularly with the newest movies and shows. That allows you to use this service without any internet connection and make it available to you free of charge.
Well now you think you will drain the battery of your device and can’t call your friends anymore to pick you up after you arrived. Alaska Airlines also has a solution here. Like most planes nowadays, they offer standard and USB power outlets. This allows you to charge your phone, tablet or laptop during the flight. Not to long ago this was a premium feature for Business and First Class passengers.
On my next flight with Alaska I will try to put the system to a test and see how well it works. Hopefully my next plane will be equipped with this service.