The creatures gathered at the dinosaur water hole include animals exclusive to different time periods. Stegosaurs lived only in the Jurassic Period, Ceratopsians only in the Cretaceous, and Dimetrodons only in the Permian. It is possible that this was not yet known in 1940.
When introducing the "Pastoral" sequence, Deems Taylor mixes Greek and Roman names of deities: Bacchus, Vulcan and Diana are Roman; Zeus, Iris and Morpheus are Greek. Apollo is the only one whose Greek and Roman equivalents have the same name.
In the full-length introduction to the "Nutcracker Suite", heard only in the roadshow version of "Fantasia", Deems Taylor states that this music is from a longer ballet called "The Nutcracker", which "nobody performs it anymore". The full-length "Nutcracker" had not been performed in the U.S. yet in 1940, but in both Russia and England it had been staged in 1934, and had already been staged in Russia twice before that, in 1892 and 1919. However, although the "Nutcracker Suite" was immensely popular even in 1940, the full-length ballet was still a long way off from becoming the annual phenomenon it now is in the United States.
In the "Sorcerer's Apprentice" sequence, as Mickey Mouse
waves his hands in front of him to make the broom come to life, his sleeves spill over his hands. It then cuts to his shadow on the wall, where his hands are fully exposed.
When the Pegasus foals are jumping in the water, the blue one jumps in, becomes the orange one, then the blue one surfaces and the black one, who is shown diving afterwards, and the pink one is suddenly in the water.