This announcement made my day. I will definitely use it for long trips and even while commuting.
Few things you need to know:
- works only on smartphones (iOS and Android)
- all videos have an expiration date and they will be deleted automatically afterwards
- for ~ 1 hour of video you'll need ~280Mb for standard definition or ~ 440Mb for high definition
- you cannot access video with your file manager (similar to Spotify offline content)
Gizmodo has a full article describing how it will work in detail: Everything you need to know about Netflix downloads