He does not believe in the checks and balances of government, preferring the executive branch to not have to answer to directives from other branches. This is at least the message he sends out to his base when he tweets that he'll ignore a Supreme Court ruling or a House subpoena. He does not believe that the justice system should be independent of the executive branch, admitting that the Russia investigation was a factor in firing an FBI director and having instructed members of his staff to try to interfer in investigations, if the Mueller report is to be believed. He places a very strong emphasis on national unity and uses language which excludes people from this national identity.

Now, there are plenty of things he does though that is incompatible with the strict definition of fascism. He clearly does not favor a mixed economy and instead prefers not to regulate it (but he does favor national self sufficiency, which was a big part of early 20th century fascism, but not even close to degree of "if the nation needs something we don't have, let's expand"), he has not tried to use the education system to strengthen the national identity (in contrast to Russia or Turkey for example), has not engaged in "moral hygiene" preachings and ... I could go on, he does not embrace all the core tenets of fascism but he does incorporate several troubling elements of it.

https://en.wikipedia.org/wiki/Fascism