The issue of unions is discussed by both Fascists and by Communists, both of whom believe that the idea of Capitalism is flawed. They see the formation of unions in that flawed system differently, so we must first discuss the flaws they believe exist in Capitalism.
This will be an extreme oversimplification, but it works for our purposes. In Capitalism, the basic idea is that businesses need a job done. Workers need to get things to survive (food, clothing, shelter, etc.)