The Pentagon and the Qatari government are close to finalizing the deal that will turn a $400 million 'flying palace' into President Donald Trump's next Air Force One.

Qatar will send the $400 million Boeing 747 aircraft as an unconditional “donation” to the Department of Defense, The Washington Post reported.

The aircraft - valued at $400m - is being donated by Qatar as an "unconditional gift", with any retrofitting costs being borne by the US government.