President-elect Donald Trump has urged the government to cancel Boeing's new Air Force One plane, saying the project was too expensive.

"The plane is totally out of control, it's going to be over $4 billion, it's for Air Force One program. I think it's ridiculous. I think Boeing's is doing a little bit of a number. We want Boeing to make money but not that much money," Trump told reporters in the lobby of his Trump tower.

Trump first made the comment in a Twitter post.

"Boeing is building a brand new 747 Air Force One for future presidents, but costs are out of control, more than $4 billion. Cancel order!" Trump said in his Tweet.

The US Air Force awarded Boeing an initial contract worth $25.8 million. Details about the total value of the new contract have not been released, but the Air Force has previously said that it had earmarked $1.65 billion for two replacement jets.

NOT A 'VANILLA' JUMBO JET

Boeing officials were caught off guard by Trump's comments since the company is simply meeting requirements mapped out by the Air Force in consultation with the White House, said defense consultant Loren Thompson, who has close ties to Boeing and other companies.

Thompson said the cost of the contract is high because of the plane's unique security requirements and communications equipment.

"Air Force One has unique mission requirements, including possibly having to operate in a nuclear war," Thompson said. "Of course it's not like buying a vanilla Boeing jumbo jet."

US presidents have used Boeing planes since 1943, according to the company's website.

The 747-8 planes, 73 meters long with a wing span of 68 meters, can fly direct from Washington to Hong Kong, 1,600 km farther than the current Air Force One.

In a September 2015 Rolling Stone profile of Trump, early on in his presidential campaign, he was quoted as gushing about the capabilities of his own Boeing plane.

"I bought this from Paul Allen and gutted it top to bottom. It's bigger than Air Force One, which is a step down from this in every way. Rolls-Royce engines; seats 43. Did you know it was featured on the Discovery Channel as the world's most luxurious jetliner?" he said.