President Trump unveiled on Friday the red, white and blue 747 Boeing jetliner donated by the government of Qatar that will serve as the new Air Force One, closing the chapter on the aircraft that had carried presidents for more than three decades.

The donated luxury jet, which prompted scrutiny from lawmakers, replaces two baby-blue planes that served as the presidential planes since 1990 and have been suffering from maintenance problems.

“This plane was transformed into a flying White House at a level of luxury that nobody’s ever seen before,” Mr. Trump said during the announcement in a Joint Base Andrews hangar that the president said had to be constructed to house the new plane, which is larger than its predecessors.

“These are the colors: red, white and blue,” Mr. Trump said. “And we like the baby blue, but it was time for a change, and this is the sleekest line.”

Mr. Trump argued that the new plane, painted with the words “United States of America,” was needed after he noticed that other nations had planes that looked better than Air Force One. The revamped plane is the latest example of Mr. Trump’s efforts to reshape signature pieces of the presidency or Washington — such as the Oval Office, the White House ballroom or the Reflecting Pool — in an image tailored to his liking.

Mr. Trump said he expected the new Air Force One to lead a flyover of Washington on July 4, trailed by F-22 and F-35 military aircraft.

For more than a decade, Democrats and Republicans alike have indeed complained that the planes used for Air Force One, which is the designation given to any Air Force plane carrying the president, are cramped and in need of replacing.

But Mr. Trump’s decision to accept a free jetliner from Qatar, which industry executives have estimated is worth about $200 million, also prompted questions from lawmakers about whether Qatar might be trying to improperly influence the president.

Mr. Trump has brushed off ethical concerns about the gift. On Friday, he said Qatar was “so nice in providing” the jetliner. “We were at a little bit of a log jam,” he said.

Mr. Trump was referring to the series of delays for two Boeing 747-8 planes that the United States procured in 2018. They are not expected to be finished before the end of Mr. Trump’s second term. The Qatari jet is intended to bridge the gap.

The Air Force said in a statement on Friday the new “bridge” plane would soon begin “initial commissioning flights,” which serve as the “final exam” before it carries the president.

Last year, Troy Meink, the Air Force secretary, told Congress that any civilian aircraft would require “significant modifications” to be considered secure enough to carry Mr. Trump. Those modifications would run “probably less than $400 million.”

Lawmakers also said they were concerned that Mr. Trump’s eagerness would not allow the Air Force enough time to install sufficient security systems against missiles or the electromagnetic effects of a nuclear blast.

The Air Force has been working since September on upgrading the jet so that it is ready to transport Mr. Trump, who has pressed for it to be available as soon as possible.

The interior design of the plane includes a mix of leather and various shades of tan and gold. The plane houses a conference room with four captain’s chairs around a square desk, as well as a television and a framed print of a duck swimming in the Reflecting Pool on the wall.

Mr. Trump said his flight home early Thursday morning from his dinner at the Palace of Versailles with President Emmanuel Macron of France was the “last planned” flight for the old presidential planes. Some of his aides posted farewell testimonials to that plane on social media.

“Well done, good and faithful servant,” Steven Cheung, the White House communications director, said on social media on Thursday.

Mr. Trump said he planned on memorializing the planes.

“We’ll probably do the museum thing,” Mr. Trump said before boarding Marine One, the presidential helicopter, for a weekend at Camp David, Md. “They’re great planes, had great history.”