Don Cheadle isn't changing his opinion about President Trump one bit ... and he's got some strong feelings about his consequential first few days back in the White House.

TMZ caught up with DC Thursday at LAX, where he said his emotions about the prez are already well-documented, but he emphasized ... "He's not starting off great, clearly."

Don wasn't specific, but seems like he's referring to Trump's boatload of executive orders signed hours after his inauguration, including one outlawing DEI, and another declaring there are only two sexes -- male and female.

The Avengers actor is a vocal ally of the LGBTQ+ community and even wore a "Protect Trans Kids" shirt on "Saturday Night Live" in 2019.

Obviously DC is not the biggest Trump fan -- he assembled his fellow Avengers back in October to show support for Kamala Harris and joked earlier this week on "Jimmy Kimmel Live" ... he wanted to run over Trump with his golf cart.

That said, Don told us, anyone who is less than thrilled about the new administration needs to stay positive -- not necessarily about Trump, but about their own role in our democracy. Watch the video ... interesting perspective.

BTW, he also has thoughts on Dave Chappelle's recent 'SNL' appeal to Trump to "do better" this time.