Animation world history:

France/Russia 

Animation during this era was more focused on propaganda videos and animated films that had no propaganda angle were frown on. 

As for the style and methods used these varied greatly from clay animation and puppets to oil  paints painted onto glass screens. most of the animation from this era was based around stop motion.

When we do see drawn  animations they are very abstract like "dots" by Norman Mclaren  or used very simple line work and lover level animation as seen in the Japanese short animations like Evil Mickey attacks Japan - A 1936 japanese animation.

In the UK we see the use of colour in animation from examples of the era. the animation has some more complex animation with  clear line work and composition. the use of story was limited in the video shown.

Overall summary of the era:

Due to the war a lot of the animations produced during this time were meant as propaganda films. there is a high use of stop motion animation during the era that ranges from oil paintings to puppets and claymation. The few animations of the era that didn't had a propaganda  meaning were quite good but had limited animation and simple characters.