Washington DC - US President Donald Trump prepared Friday to sign his flagship tax and spending bill in a pomp-laden Independence Day ceremony featuring fireworks and a flypast by the type of stealth bomber that bombed Iran.

Trump pushed Republican lawmakers to get his unpopular "One Big, Beautiful Bill" through a reluctant Congress in time for him to sign it into law on the US national holiday – and they did so with a day to spare on Thursday.

Ever the showman, Trump will now meld a victory lap over the bill – which cements his radical second-term agenda – with a grand party at the White House marking 250 years of independence from Britain.

Trump announced a signing ceremony at the White House for 4:00 PM and said pilots who carried out the bombing on Iran were among those who had been invited.

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Looking jubilant at a rally Thursday in Iowa after the bill passed, Trump said, "The age of America is upon us. This is a golden age."

The bill, which includes massive new funding for Trump's migrant deportation drive, is the latest in a series of big political wins at home and abroad for the 79-year-old tycoon and underscores his dominance over both the Republican Party and US politics at large.

His administration has meanwhile glossed over deep concerns from his own party and voters that it will balloon the national debt, while simultaneously gutting health and welfare support.

White House economic adviser Kevin Hassett on Friday rebuffed the criticism, claiming the bill will produce "a real blowout for growth."

"Nobody's going to lose their health insurance because of this," Hassett told Fox News, rejecting nonpartisan analyses estimating millions of poor Americans will lose health coverage on the government-funded Medicaid program.

First Lady Melania Trump was also set to attend the Independence Day event.

The president's wife had told reporters on Thursday that a B-2 bomber – the type of aircraft that bombed Iran's nuclear facilities on June 22 – and fighter jets would carry out a flyby for the July 4 event.

Trump told the rally-goers in Iowa that the pilots and others who worked on the mission would join him for the festivities.

"They're going to be in Washington tomorrow, at the White House, we're going to be celebrating," he said.