A day earlier the president presided over a rowdy and acrimonious press conference in the White House, where he unleashed a tirade against his critics, blasting the various leaks emanating from US intelligence agencies and attacking the media as "out of control."
Trump strenuously denied that he or his associates had improper contacts with Russian officials during last year's campaign, and defended the actions of his ousted national security advisor Michael Flynn, who resigned under a cloud this week.
Harward told CNN he bowed out because of family and financial commitments. But several media outlets reported that he was concerned about whether he would be able to shape his own NSC team.
Members of the council currently include Steve Bannon, Trump's controversial far-right former campaign manager.
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One unidentified Harward friend told CNN that he declined the job because of chaos at the White House, and called the offer a "shit sandwich."
But the president seemed to relish the opportunity to escape the Washington maelstrom and take his show on the road, returning to what was a winning campaign-trail formula: connecting with everyday Americans.
"Going to Charleston, South Carolina, in order to spend time with Boeing and talk jobs!" Trump said on Twitter.
The White House said Trump will help unveil Boeing's new 787 Dreamliner, the 787-10, which the company bills as the world's most fuel-efficient aircraft.
The US manufacturer employs some 7,500 people in South Carolina, where it has invested more than USD 2 billion since beginning operations in the southeastern state in 2009.
At campaign trail stops in South Carolina, Trump had warned audiences that they could lose the state's Boeing jobs because the jets "will be cheaper to build in China."
The former reality television star resonated with voters in large part because he directly addressed the concerns of middle-class and working-class Americans who felt left behind in the US economy.