Okay, keep in mind that these are basically spur-of-the-moment ramblings. No guarantee for coherence.
Germany
Germany is a constitutional Monarchy, with a strong aristocracy. The Weimar Republic failed in 1924, and what was left of the Aristocracy managed to reassert its control, as people looked for new strong leadership. In 1927, a team of scientists under Albert Einstein and Wernder Heisenberg managed to isolate "Flugstein" (literally "Flystone"), an element or state of matter (What exactly is still under debate in physicists' circles) that had astonishing properties. It turned out that a sufficient quantity of flystone, when subjected to an electrical current, can lift something into the sky.
This discovery was used as a bargaining chip with the League of Nations to pay off the remaining reparations for WW1 damages. All accumulated flystone research was turned over to the world public, and Germany retreated from international politics.
Taking a page from the Swiss playbook, Germany remains neutral in european politics, while at the same time rising to one of the biggest arms exporters. German-built Zeppelins are a common sight in the skies, and german flystone engines are a sought-after commodity.
This combination has the other states somewhat worried. There are indications for a massive buildup of armed forces, funds being funneled into dark channels, that hint at something massive going on in the few areas the german Air Navy has locked down hermetically.
The British Commonwealth
The last great colonial empire. Through a combination of force of arms and economy, most of Britains' colonies chose to remain in the Commonwealth. The Royal Navy was the first one to complete a total conversion of their existing wet-water navy to a flystone-equipped armada; and as a result, British forces got to write the book on modern air combat. Most of the Royal Navy is deployed running convoy escort for Zeppelins that connect the pieces of the Empire.
(I'm not going to go into details about the politics here; Someone british should fill it in)
The Rest
No idea about Russia.
As for Japan, it currently controls Korea, a portion of China, and a chunk of what was termed the Greater East-Asian Co-prosperity Sphere (excluding territories under British and American control).