Plenty of well photographed Japanese sci-fi miniatures in this rather odd film that features a flying submarine named the Alpha as well as a flying lion creature.
Below are some photos of the Alpha miniature in the Toho storeroom. It seems to be missing some parts of the rear section.
In my opinion the baddies submarine known as the Black Shark is a better looking design than the hero's submarine even if it is incapable of flight.
Visual effects supervised by Eiji Tsubaraya.