Washington. US President Donald Trump said Wednesday he is considering buying used Boeing aircraft -- perhaps from an overseas seller -- to use as Air Force One when he's aboard, as he fumes over the US plane-maker's delays in producing two specially modified ones for residential use.

Speaking to reporters aboard one of the two nearly 35-year-old Boeing 747-200 aircraft in current use, Trump said, “We’re looking at alternatives, because it’s taking Boeing too long.”

“We may go and buy a plane,” Trump said, adding that he could then “convert it.” He later clarified that he was ruling out purchasing aircraft from Airbus, the European company that is the only other global supplier of large wide-body aircraft, but would consider a second-hand Boeing plane. “I would not consider Airbus. I could buy one from another country perhaps or get one from another country."

Boeing has the contract to produce updated versions, based on the more modern Boeing 747-8, but delivery has been delayed while the aircraft maker has lost billions of dollars on the deal, which was negotiated by Trump during his first term in office.

It's not the planes, rather the heavy modification to make them suitable for the requirements of presidential travel and the top-level security clearances required for those involved, that has added to the cost and delays. Trump already dropped a requirement for the new generation of planes, which will be known as the VC-25B, to be capable of air-to-air refueling, like the pair of existing VC-25As, which were designed during the Cold War.

Other modifications include highly classified communications equipment suitable for the country's commander-in-chief, survivability enhancements for a range of contingencies, and self-contained air-stairs, allowing for their use in austere landing environments.

Delivery initially was set for 2024, but has been pushed to some time in 2027 for the first plane and in 2028 -- Trump’s final year in office -- for the second, according to the US Air Force.

Trump on Saturday toured a newer Boeing 747-800 airplane to check out new hardware and technology features and highlight the aircraft maker’s delay in delivering updated versions of the Air Force One presidential aircraft, the White House said Saturday. Trump visited the 13-year-old private aircraft that had been owned by the Qatari royal family while it was parked at Palm Beach International Airport.

The New York Times was first to report that Trump was considering purchasing and modifying used aircraft to serve as new presidential aircraft.