Asked for her impressions of the event, a clearly underwhelmed Thunberg was to the point, saying "We had a few demands (coming into the World Economic Forum)".
The heir to the British throne, who's well-known for his environmental campaigning, was pictured meeting and shaking hands with the 17-year-old Swedish environmental activist following his address.
But either by accident or design, there was no meeting between Trump and Thunberg at the forum.
At a news conference before the march, she acknowledged young climate activists "are being criticized all the time" in comments like those from U.S. Treasury chief Steven Mnuchin.
"They do not have to do anything as they are not being held accountable", she lamented before joining other young people in one of her regular "Fridays for Future" protests in Davos. "Who is she? I'm confused", adding after a pause that it was "a joke".
"We can not care about those kinds of things", Thunberg said, insisting that her priority was drawing attention and action to concerns about global warming.
She cautioned that while world does not treat, "this crisis as a crisis, and as long as the facts are ignored, we will not solve this crisis".
"If we were careful we could not do what we do".
Those remarks earned her a rebuke from US Secretary Steven Mnuchin who told her to "study economics" then 'come back and explain it to us'.
Thunberg and her climate advocates have also come in for criticism from some longstanding environmental advocates over tactics, if not necessarily their ambitions.
"We never striked for discourse change", said Neubauer, who this month turned down the offer of a board seat on a subsidiary of German industrial giant Siemens. "But not in an aggressive way".
Asked about the statements targeting her from an American minister on Thursday, Greta Thunberg said they had "no effect" on her.
Marco Lambertini, director general of WWF, defended Thunberg as the "biggest catalyst for change over the past year".
He said the reason the United States left the Paris climate agreement - which calls for blocking global warming at well below 2C, and 1.5C if possible - "was not because we don't support the environment (but because) we thought it wasn't a fair and balanced agreement".