WASHINGTON, United States (AFP) — US President Donald Trump faced questions about the security of his new Air Force One plane gifted by Qatar, after he took an older jet home from a North Atlantic Treaty Organization summit this week.

The billionaire president has been unable to contain his excitement over the retrofitted Boeing 747-8 aircraft, which took him to Ankara on its maiden trip outside the US.

Trump then abruptly announced in Turkey that he would send the aircraft ahead to a British airbase saying the decision was made to allow US troops to tour the luxury plane.

The New York Times reported on Friday that the new plane lacked the same security countermeasures boasted by the older jet, including anti-missile defenses. US media also reported that the Secret Service had advised the switch.

Speculation was fueled by the fact that US hostilities had flared again with Iran, which borders Turkey, and because journalists on the old plane out of Ankara were also told to keep their window blinds down, a step normally reserved for war zones.

Trump himself denied any security concerns, but after switching back to the new plane for the flight from the UK to Washington, he referred to alleged Iranian assassination attempts.

"You're probably on a dangerous flight because of the sleazebags we have to deal with," he said.

The White House defended the new plane's safety.

"The new Air Force One is a state-of-the-art aircraft that has been fitted with high-level security protocols that ensure the safety of the President and his staff," Communications Director Steven Cheung said in a statement to Agence France-Presse on Friday.