According to the Operation Services Coordinator for Regal Entertainment Group the popcorn served at the Regal Movie Theaters is popped in canola oil and is gluten free. The buttery topping is also gluten free.
There is a lot of information on the internet about movie theater popcorn. I have not checked all of the movie theaters but a majority if not all that have responded to questions regarding the GF status of their popcorn have confirmed that it is GF. Recently, however, there was some confusion as to whether the buttery topping on the popcorn at Regal Entertainment Groups is GF or not.
The Savy Celiac reported that "the popcorn is gluten-free but the buttery topping is not" and listed the ingredients in the buttery topping as: “Partially Hydrogenated Soybean Oil, Soy Lechtin, TBHQ & Citric Acid to improve stability, Natural & Artificial Flavors & Colors, Dimethylpolysiloxane (an anti-foaming agent)”
None of these ingredients jump out as having gluten in them. Since we occasionally like to eat popcorn at this movie theater I decided to follow up on this information.
I made contact with Jami Miller, the Operational Services Coordinator for Regal. I shared with him the report on Savy Celiac and after a month of exchanging emails he confirmed that he checked with the Food Services Department and both the popcorn and the buttery topping is in fact gluten free.
I can only report the information that is shared with me and you should always independently confirm that food is gluten free before consuming it yourself. You should also confirm the risks of cross-contamination at your local movie theater.