Downloaded iTunes movie rentals won’t play offline

Why won’t rented iTunes Store movies that I have downloaded play on my iPad when I’m offline (on a plane without WiFi).

Twice in the last week I have rented a movie from the iTunes Store to watch on a flight (something I’ve done dozens of times in the past). Both times I have confirmed that the movie is downloaded before boarding the plane but, when I try to play the movie in flight, I get an error that says “content not authorized” and the movie won‘t play.

In both cases the movie shows up under the “Downloaded“ drop down in the TV app and, in both cases, the movie plays without an issue when I turn airplane mode off and reconnect via WiFi or Cellular (but neither flight had WiFi available so I suspect that Apple is attempting to re-verify the downloaded content before allowing it to be played and is unable because my device is totally offline).

I have no problem playing purchase iTunes Store content or downloaded content from Netflix and Amazon Prime so this problem appears to be isolated to iTunes Store movie rentals.