"After Brexit 2016 and Trump 2016 things have changed and someone needs to take the leadership, and the fact that Macron and Merkel are doing that, I welcome it", Alexander Stubb, Finland's former prime minister and now vice president of the European Investment Bank, told AFP.
Trump is set to meet with Rwanda's President Paul Kagame during the World Economic Forum in Davos, which draws A-listers and global leaders from the worlds of politics and business.
Mr Trump arrived in Davos, Switzerland, on Thursday for his first appearance at the World Economic Forum.
Trump, never invited as a businessman, will be the first USA president to attend Davos since Bill Clinton in 2000, giving him a chance to mingle with the same elite "globalists" he bashed in the 2016 election campaign.
Trump arrived earlier in the day after an overnight flight from Washington and a scenic helicopter journey over the Alps from Zurich.
In a tweet sent before departing the White House Trump said, "Our economy is now booming and with all I am doing, will only get better ..."
Jo Swinson, deputy leader of Britain's Liberal Democrats, the fourth-biggest party in parliament, said: "Trump is a unsafe, misogynistic racist and is deserving of the protests he will undoubtedly face".
Mr Trump said that decision has consequences.
But he drew enthusiastic praise for his tax-cut law at a dinner that he hosted Thursday for more than a dozen business executives from Nokia, Adidas, SAP and other companies, with the business leaders praising his tax plan and pledging to invest more in the United States before their tucked into their beef tenderloin.
The fact that Macron also candidly addressed France's own challenges in adapting to a globalised world - in smooth English, no less - only reinforced his stature as a global counterweight to Britain and the US.
But some delegates praised the president ahead of the summit for boosting the United States economy and getting consumers spending again.
US Commerce Secretary Wilbur Ross argued that new US tariffs on imported solar-energy components and large washing machines are meant to deal with "inappropriate behaviour" by other countries and are not protectionist.
In a statement, the progressive campaign group that hung the banner, Campax, said it hoped the USA leader would see it as he flew by in his helicopter.
Trump smiled and waved as hundreds of onlookers at the elite gathering lined the lobby and a high staircase of the conference venue in the Swiss resort to get a glimpse of him.
With Netanyahu, the discussion before the cameras concentrated generally on the president's declaration a month ago that the US would perceive Jerusalem as Israel's capital and start the way toward moving its government office there.
They discussed Iran and Syria, while May briefed Trump on the "good progress" in Britain's negotiations on leaving the European Union, Downing Street said.
Trump's decision past year to recognize Jerusalem as Israel's capital roiled Arab nations and led Palestinians to withdraw from negotiations on the grounds the USA can no longer be trusted as an honest broker in the quest for peace.