President Donald Trump flew back to Washington from the Nato summit in Turkey late on Wednesday aboard the older Air Force One, rather than the new Boeing 747-8 given to the US by Qatar.
US media reported the switch was made at the request of the Secret Service as a security precaution after the latest escalation with Iran.
Reports also said the new aircraft lacks the same level of missile-detection systems as the older presidential jet.
The White House denied those claims, saying the Qatari plane is “state-of-the-art” and equipped with “high-level security protocols” to ensure the President's safety.
"As the President has said recently, there are many enemies of America who have their sights on him, and we use every tool at our disposal – including distraction and misdirection – to address those threats," White House communications director Steven Cheung said.
It was the first overseas journey for the Boeing 747, which Qatar gave to the US last year.
The aircraft drew criticism over security concerns and potential conflicts of interest, with the US spending about $400 million to retrofit it for presidential use.
Mr Trump said on Truth Social that he had switched planes “for old time's sake” and to give service members at RAF Mildenhall in the UK an opportunity to tour the aircraft.
The change came after Mr Trump ordered a new round of strikes on Iran on Tuesday and declared the ceasefire “over”.
On Tuesday and Wednesday nights, US forces struck dozens of targets along Iran's coastline. Iran responded by launching drones and missiles at US military bases across the Gulf and in Jordan, raising fears of a return to full-scale war.
During the two-day summit in Ankara, Mr Trump acknowledged he had concerns about his safety.
“I speak about it a lot because the life of a president is very dangerous,” he said. “I'm number one on the kill list for Iran.”
Iran is holding a week-long series of funeral processions for Ayatollah Ali Khamenei, the former supreme leader who was killed on the first day of the US-Israeli war in late February.
Footage from the funeral showed mourners carrying signs reading “Kill Trump”.
Mr Trump has been the target of at least two previous assassination attempts, including one in Pennsylvania in 2024, when a bullet nicked his right ear.
