True communism and true fascism are totally different because ideal communism would involve communes and people running an area as a group with no leader. However when put into practice over millions of people communism and fascism are very similar. True fascism is very close to what people think today, if not spot on. Communism works much better with smaller groups of people. When put over a very large number of people it doesn't work (examples: USSR, China). Fascism doesn't work in any sized group.
Communist economies do not work at all with a large military (examples: USSR, North Korea). The Soviets also had an empire to maintain, which made it worse. Both types with large militaries tend to have extremely egotistical leaders who make having a military seem like a bad thing. Fascist nations tend to be more expantionist (example: Italy 1922-43). That bogs down the fascist economy. All in all it is not good to have communism or fascism and have a huge military.