A senior US Air Force figure has said he has no knowledge of claims made by President Donald Trump that he had cut the cost of upgrading it's Air Force One fleet by $1bn by purchasing two new jets. The comments were made by Trump at a rally in Florida last week.

Trump has been critical about the projected expense of the upgrade to the US president's jet, tweeting in December that the "costs are out of control". Trump reiterated his thoughts on the matter during the campaign rally, in which he also referred to a fictional terrorist attack in Sweden.

Speaking at the rally, Trump said: "They were close to signing a $4.2bn [£3.37bn) deal to have a new Air Force One. Can you believe this?

"I said, 'No way.' I said, 'I refuse to fly in a $4.2bn airplane. I refuse.'"

Trump said that instead he had been able to bargain with Boeing, claiming "we got that price down by over $1bn, and I probably haven't spoken, to be honest with you, for more than an hour on the project. I got the generals in, who are fantastic. I got Boeing in. But I told Boeing it's not good enough. We're not going to do it. The price is still too high."

Air Force One is operated by the Presidential Airlift Group, which is part of the White House Military Office. However, it was reported by Bloomberg this week that when asked about the savings this week, Airforce Spokesman Colonel Pat Ryder told reporters: "To my knowledge, I have not been told that we have that information," adding, when pressed on the savings, "I refer you to the White House."

Though the codename Air Force One refers to any aircraft which the president is travelling in, since 1943, the US president has had his own private jet for official business. The current jet, which was first used almost 30 years ago in 1990 and has served Presidents George Bush Snr, Bill Clinton, George W Bush and Barack Obama, is overdue an upgrade.

It is the sixth Boeing fleet to be used by the White House, with the first, a Boeing 314 Clipper, initially used by Franklin D Roosevelt. John F Kennedy was the first president to fly in a jet specifically built for presidential use.

The current presidential jet is a Boeing 747-200, which boasts quarters for the president and first lady and office space, including one office that convert into a medical facility with an operating table, within its 4,200 square feet of floor space.

The so-called "flying Oval Office" also has advanced communications systems and is capable of mid-air refuelling.

Barack Obama Air Force One China
The current Air Force One jet has been in use since 1990.Jonathan Ernst/Reuters