US President Donald Trump left Turkey on Wednesday evening on the older presidential plane instead of the Boeing 747-8 gifted by Qatar, as a security precaution following the resumption of combat operations with Iran, according to people familiar with the arrangements, who said the decision was 'based on a recommendation from the US Secret Service.'

The New York Times said this change raises questions about whether the new plane, which Trump pushed to be ready as quickly as possible, had undergone sufficient security upgrades over the past year.

Lawmakers and some officials had expressed concerns that the rapid timeline may not have allowed for the installation of an advanced missile defense system and other modifications needed to protect the president.

White House Communications Director Steven Cheung said in a statement that 'the new presidential plane is a highly advanced aircraft equipped with high-level security protocols to ensure the safety of the president and his crew.'

He added: 'As the president has said, there are many enemies of the United States who have made him a target, and we are using every tool at our disposal, including distraction and deception, to address these threats.'

Advice from the Secret Service, not a threat

But people familiar with the capabilities of the new plane, who spoke to The New York Times on condition of anonymity due to the sensitivity of security information, said the new plane does not have all the features of the older one. They added that the decision to switch planes when leaving Turkey was a precautionary measure based on advice from the Secret Service, not because of a specific threat.

Trump, who has repeatedly praised the amenities of the new plane, used it on Monday evening to travel to Turkey for the NATO summit.

After his arrival, fighting with Iran resumed, with the US launching a series of strikes on Iran while Trump and NATO leaders were about a thousand miles away in Ankara.

"Iran's top target"

On Wednesday, Trump denied that the plane change was for security reasons, insisting the goal was to allow the new plane to head early to US military bases to show it to troops because it is 'amazing.'

But when journalists in Ankara asked him about the reason for the change, Trump repeatedly said he was 'Iran's top target,' and at one point indicated that he had been briefed in recent days about a list of targets drawn up by Tehran.

Earlier Wednesday, Trump wrote on Truth Social that he would leave Ankara on the old plane 'for old times' sake,' so that the new plane could head to Mildenhall Air Base in Britain to give US troops a chance to see it.

The Secret Service declined to comment, only pointing to the president's post as an explanation for the change.

When leaving Ankara, Trump boarded the old plane unusually quickly, before accompanying journalists could watch or photograph him boarding as usual. Passengers on the plane were also asked to close the window shades before takeoff.

Trump boards new plane from Britain

The plane landed at Mildenhall Air Base late Wednesday evening, before the president transferred to the new plane to continue his trip to Washington.

After leaving, Trump told journalists that they were probably asked to close the plane's windows when leaving Ankara because they were 'on a plane at risk' due to the Iranian threat.

Reports indicate that the old plane is equipped with a system capable of diverting anti-aircraft missiles aimed at it, as well as chaff dispensers to deceive missiles and divert them from their path.

It remains unclear what capabilities, if any, have been installed on the new plane, which Trump was keen to put into service quickly.

New plane upgrades

Aviation officials and the Pentagon said such a massive upgrade could cost up to $1 billion and take up to two years. But US Air Force Secretary Troy Meink estimated before Congress that the modifications would 'likely cost less than $400 million.'

The US Air Force began upgrading the 747 aircraft within the United States last summer.

Air Force officials at the time said the aircraft was undergoing modifications to support 'executive transport' capabilities under orders from Secretary of War Pete Hegseth, stressing that all other details of the upgrade are classified.

The plan drew criticism from some members of Congress, who expressed fears that Trump would pressure the Air Force to finish the work quickly at the expense of necessary protective measures, including missile defense systems or even systems that protect the aircraft from electromagnetic effects of a nuclear explosion.

Most of the upgrade and renovation work announced by the Air Force took place at a facility in Texas known for carrying out secret technology projects.

Essential structural modifications

Andrew Hunter, former Assistant Secretary of the Air Force and responsible for the Air Force One program under former President Joe Biden, said converting a 747 aircraft into a presidential plane with Air Force One specifications requires more than a year of work.

He explained that the base aircraft, even if it has luxury interior fittings, needs substantial structural modifications to accommodate special security systems, which would have taken longer than the time available for the plane's upgrade.

Hunter declined to disclose details of the most complex protection systems because they are classified, but other government officials told The New York Times that these modifications include advanced missile defense systems, as well as reinforcing the aircraft's wiring to protect against electromagnetic pulse in the event of a nuclear attack. It remains unknown whether these modifications have been made to the plane.

Hunter said: 'In the time frame that was available, it was possible to implement upgrades to communications systems,' referring to equipment that allows the president to stay in constant contact, 'but not any modifications requiring major structural work.'

He added: 'Carrying out a full upgrade equivalent to Air Force One specifications does require structural modifications.'

The New York Times had asked the US Air Force earlier this year whether these systems had been added to the plane, but the Air Force declined to answer questions.