Donald Trump secretly switched planes when he was returning from a Nato meeting last month in order to avoid a threat to his life from Iran, US media has reported.
The president boarded Air Force One in Ankara, Turkey, on 8 July before being transported to another aircraft with the help of a catering truck, the Washington Post said.
He was then seen disembarking Air Force One in the UK, before boarding his newer, Qatari-gifted jet and returning to the US.
Trump spoke to journalists during his flight to the US but did not say whether he had been moved to a different plane.
The BBC's diplomatic correspondent Paul Adams explains.
