Fascism is a reactionary attempt to “turn back the clock” to the glory days of Capitalism before it decayed as much. Capitalism necessarily results in crisis, at which points occasionally the Bourgeoisie and Petite Bourgeoisie, the “middle class,” work together against the lower classes, ie the Proletariat and Lumpenproletariat. It usually rises as a response to climbing Socialism as the train of thought among the Proletariat.
It isn’t necessarily modeled after anything, history isn’t driven by ideas but Material Conditions and class conflict.