I was watching my dvd of Sonic the Movie and during the credits I saw something that shocked me.
If you look as the credits for Animation and Finishing as they scroll by you see Tezuka Productions listed (3 times). I have seen this movie over and over ever since it came out on VHS and never realized Tezuka Productions helped animate this film.
This is interesting considering that later on Sega would work for Tezuka Productions by creating the Dororo: Blood Will Tell and Astro Boy game for the PS2. As well as Astroboy Omega Factor for the GBA and Black Jack: Hino Tori Hen for the DS.
I've loved this movie before (I considered it the best Sonic Animation ever) now I have even more respect for it.