Dictatorship and fascism are two different things. Hitler was elected by a purely democratic nation in a purely democratic fashion. Hitler was a fascist.
In my opinion fascism is an ultra-nationalism, believe that your nation or ethnic group are above everybody else. Remember Hitler's Aryans were above the rest? That's fascism. For example, the whole concept of "American exceptionalism" to me sounds like a purely fascistic notion.
Nationalists are usually patriots. Fascists, in addition to being patriots, are also "superiorists", i.e. we're better then everybody else and as such we deserve to be treated better then everybody else.
Is America a fascist nation? We'll see. Nationalism does not necessarily mean fascism. Russia was ultra-nationalist in the 90s but I'd never call it fascist. I mean there are and always have been fascists there, like anywhere else but as long as they constitute the fringe it doesn't make a nation fascist.
Despite of me customarily referring to Trump as Il Duce (talks the talk and looks it a bit too, doesn't he?), I don't consider Trump fascist. At least not yet. His motto: "America first!" is nationalistic but it doesn't point to him thinking of Americans as superior. Moreover, I know that I heard and read numerously that Trump doesn't like and doesn't agree with the notion of American exceptionalism, which is something which makes me hopeful in regards to the world's peace under Trump/Putin administrations. On the other hand of course, Trump's propensity to "chase shinny objects" moderates that hope significantly.
So in short:
Nationalism - I love my country, I love my people. You fuck with us, we'll unload on you more then you can handle.
Fascism - my country is better then any other country, my people are better (as in superior) then everybody else and as such we should be treated differently then everybody else, and everybody else should pay homage and maybe be even ready to serve us (like Hitler's Aryans and Mussolini's Romans). Fascism can also be outwardly aggressive or not.
In short, fascism is a nationalism that emphasizes national superiority above everything else. I think I got it right..