There are enough definitions of fascism that you could probably find one that applies, but I think the only sense that really fits is as a pejorative for authoritarian right-wingers in general. He's certainly an oligarch, being rich enough to fund his own campaign was part of his pitch early on.
Only tangentially related I guess, but I've got an article from socialistworker in my rss reader right now drawing a parallel (not as the point of the text, just in passing) between Trump and Berlusconi.Thus, the White House, once dominated by old-money ruling class figures and politicians socialized in the U.S. military, will now be occupied by a rogue billionaire. Trump, despite the comparisons some have made to the Italian fascist ruler Mussolini, more closely resembles Silvio Berlusconi, the Italian media magnate who used his money and populist appeals to impose himself on a corrupt, conservative political establishment.
There was a poll early in the GOP primary that correlated support for authoritarianism with support for Trump, and the correlation crossed ideologies. Fascist, oligarch, autocrat. The point is kind of moot, IMO, since taxonomy is far less important than the result.