Did you make sure that the Netflix movie or TV show was one that was downloadable?
In the Netflix App, you can set your search to find all of Netflix's downloadable content.
Not ALL Netflix content is, currently, available for download.
Choose the movie or TV show and there should be a download arrow to tap to allow the movie to download to your iPad inside of the Netflix app.
I just tested this feature by downloading a TV episode and turning off my Wifi connection on my iPad and I was able to play the TV show, no problem.
You play the downloaded movie from a special downloads area inside of the Netflix app.
Good Luck!