Yes, in a very, very specific context.
Both men were demagogues using appeals based on race, national power, national humiliation, anger, anxiety and xenophobia to stoke a dominant majority into mobilizing to protect their perceived interests.
Both men represented a response to democratic pluralism, any kind of multicultural tolerance, and perceived economic anxieties thanks to a recent recession/depression.
Both men advocated war crimes and torture.
Both men used a macho strongman politic.
Of course, even in that context, the comparisons between the two break down rapidly, at least at the level of details. Hitler would be more like if Trump had run as an independent: he came out of a third, far-right party, then managed to gain power through an array of lucky breaks and deliberately vile acts. Trump, on the other hand, basically hijacked an increasingly moribund conservative party and turned it into a far-right party.
Mussolini is actually the better comparison. Trump doesn't invoke the same kind of truly bizarre conspiracy theories Hitler did, nor does he have the kind of "ordinary soldier worked his way up" mystique. Mussolini's bluster is more akin to Trump's: Hitler was more fiery and overtly collectivist in his logic. Trump isn't openly invoking the idea of a white race.
The reason why the comparison is too close for comfort is not only the violence at Trump's rallies and the way Trump has not only advocated violating the First and Sixth Amendments but also famously feuded with and mistreated the press (to the point of his former campaign manager quite clearly assaulting a reporter that was on their side), but also the sheer reality that the man is running with the alternative right, who are really just far-right racists who are dumb enough to think that they're original. Hillary Clinton's "basket of deplorables" comment about Trump supporters is actually accurate: About 20% believe that Lincoln should not have freed the slaves, 16% think that whites are the superior race (at least in South Carolina), flat majorities think Obama was not born in America and is a Muslim (and apologists can spare me the idea that either of those are not overtly bigoted views), and Trump supporters are more likely to view blacks negatively than the average member of the population. It's just flatly inaccurate to say that Trump supporters are generally motivated by a feeling of corruption in the political system, since most did nothing after Citizens United or while Bush was in charge; or that they are motivated by economic insecurity, since he's polling at single digits with African-Americans who are certainly not alien to economic insecurity; or that they are motivated by an anti-elite sentiment, in that they could easily vote for someone like Dr. Jill Stein but instead are voting for a billionaire who rubbed elbows with the very elite they claim to despise. No, every one of those ideas has to be understood through a specifically racial lens.
The Trump phenomenon is far-right politics. It's scary enough in Europe, but it's far, far more dangerous here, when a man with that kind of narcissism and clear willingness to play bigots for all they're worth will be in charge of nuclear weapons.