"The Flying Mouse" is a parable about a mouse who longs to have wings and fly with the birds.  He attempts first to use two leaves as wings, with disappointing results.  However, a strong breeze suddenly blows him this-a-way and that-a-way.  He comes across a butterfly who has found herself caught in a spider's web.  Armed with a small twig, the mouse fends off the menacing spider and frees the butterfly.  She then transforms into a beautiful fairy, who rewards the mouse with one wish.  He wishes more than anything to have wings and fly, and soon, brown wings sprout from his back.  

It takes a little while to get used to flying, but the mouse masters it quickly, and proceeds to join some birds chirping on a branch.  The birds are terrified of this new flying mouse, and all fly away to their nests.  When a little bird tries to befriend him, the mother bird takes it away.  Lonely, the flying mouse decides to fly home and join his brothers in a game of leap frog.  However, as he flies down, his shadow resembles that of a bird, and the family of mice hide inside their pumpkin house, refusing to let him in.  Despondent, the mouse flies away, and finds himself among some bats.  In short, they terrify him and he flies out almost as quickly as he came, only to find the fairy again.  He begs her to take away his wings, which she does, as he has learned his lesson: be careful what you wish for.

"The Flying Mouse" isn't particularly engaging.  In fact, I found myself almost falling asleep by the end of the cartoon, something that rarely happens.  Especially when the cartoon is only 9 minutes long.  But it simply doesn't do much beyond present the cutesy-cute characters in a simple morality tale.  I could try to analyze it further and say why the short is significant, but that would be overreaching.  And to be honest, there's not much else to take away beyond "be careful what you wish for".

1934, the year this short came from, was a transitional year for Walt Disney Studios.  Walt had begun his plans for a feature-length animated cartoon, Snow White and the Seven Dwarfs, and the animators began experimenting with more realistic depictions of the human body and its movement.  Many cite "The Goddess of Spring" as the first attempt, and I don't challenge that.  The rubbery movements of the characters in that short are almost laughable today, but was an improvement over previous attempts in the Silly Symphonies.  "The Flying Mouse" has a prime example in the fairy, who looks woefully anorexic and her clunky movements feel like a before-its-time early animatronic.  And as stated before, much of the animals here are cutesy-cute, even the bats feel almost huggable.