The cost to rehab the controversial luxury jet generously gifted to Donald Trump by the government of Qatar remains a mystery with the figures not being made available at the same time that there are questions about a "mysterious" Pentagon fund transfer.

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

The free Air Force One from Qatar, which Trump has described as a gift, has raised eyebrows after a $934 million transfer of funds was made to an unnamed classified project from the Pentagon, with officials in the Air Force saying that millions of dollars were needed to pay for renovating the aircraft.