Yeah, I believe it was pretty much just Fleischer’s at the time who were trying the two-reel cartoon method. Disney did experiment with longer-form cartoon shorts in the 1940s, but they were usually included as part of package features (Warner’s never got this far. If I recall correctly, I think the longest Warner Bros. cartoon was HORTON HATCHES THE EGG, which was a little less than 10 minutes). Fleischer’s had the ability to do this because of Popeye’s popularity with audiences (at some point in the 1930s, he had surpassed Mickey Mouse in popularity).
HomokHarcos probably knows this already, but there actually were animated feature films before SNOW WHITE. They mostly used less common forms of animation like stop motion or cutouts (the earliest surviving animated film, THE ADVENTURES OF PRINCE ACHMED, used a special form of silhouette animation). SNOW WHITE was the first completed feature to use the more commonly known cel method, hence why most tend to consider it the first animated feature.
