President Trump was entranced. It was a few weeks into his second term, and he was on the tarmac of the Palm Beach airport, getting a tour of a luxury Boeing 747-8 that had been flown from Doha for his perusal.

The double-decker jet, which had been outfitted for the Qatari royal family, had a spacious bedroom adorned with leather and wood and a lounge featuring a chandelier and another with suede seats.

Two planes being built by Boeing to replace the aging Air Force One fleet were years behind schedule, and Mr. Trump’s team had asked the Air Force to find a temporary aircraft. This was the one, the president decided.

Mr. Trump’s February 2025 tour of the Qatari jet led to a frantic sprint inside the White House and the Pentagon. The administration sought to upgrade the plane in time to meet his demand for it to be ready by the nation’s 250th birthday this summer, with an accelerated retrofit.

An investigation by The New York Times found that the president’s push to get the luxury aircraft quickly led to ballooning costs and trade-offs in safety features that potentially left Mr. Trump and others who travel with him on Air Force One vulnerable.