On occasion, I've noticed that the Cinemark Connections app has a reward for a free RT flight on United to any US destination (can't remember if it includes HI, AK, PR, etc. but I think it did) for 1000 Connections points. It seems to come and go sporadically, but I have seen it reappear a few times over the past couple of months.

The max daily earning is 30 points: 10 for CineMode (can do every day, even if not at the theater), 10 for buying a ticket, and 10 for a concessions purchase. In theory, you could earn 1000 points for doing CineMode every day for just over 3 months. Just a reminder that you could earn a free flight by going to the movies.

If you're coming up short, you can always redeem for a free small drink at 190 points.