During WWII, the output of the major animation studios consisted, in large part, of various military training films, propaganda films and the like. Sure, they still made a few of the regular cartoons, but these were also made in much smaller numbers. "The Thrifty Pig" is an example of Disney helping with the war effort. In this case, it's to advocate for folks buying Canadian war bonds. And, since it's Disney, they've resurrected some of their old stars--the Three Little Pigs. By 1941, they were pretty much passé and I am not sure if they recycled some of the old film or if it was all new. I think it was all-new, as the Wolf, for example, looked much different--he was sporting a Nazi armband! It's also interesting that Disney didn't wait until the US entered the war, as this film debuted a month before Pearl Harbor.
This preachy film begins with the pigs doing what they did in the original story...but with a twist. The two dumb pigs didn't plan for the future and built their crappy houses. But the smart one invested in bonds--which, somehow, made his house rock-solid. Following this and the obligatory wolf, the rest of the film consists of talk about the war effort and animated footage of the war production plants. For the most part, it is all very boring. But, historically speaking, it's an interesting glimpse into the times.