(AP) — President Donald Trump has reached an informal deal with Boeing to provide the next generation of presidential aircraft, the White House says.

Deputy press secretary Hogan Gidley said Tuesday that the president negotiated a $3.9 billion “fixed price contract” for the new planes, known as Air Force One when the president is on board. It follows years of negotiations between Boeing and the U.S. Air Force — and Trump’s personal intervention since his election.

In December 2016, Trump tweeted that costs for the program were “out of control, more than $4 billion,” he added. “Cancel order!”

The White House now says the original cost estimate was actually over $5 billion for the two airplanes and development program.

Boeing chief executive Dennis Muilenburg met multiple times with Trump to discuss the Air Force One contract, most recently last week.

Gidley said the agreement would save the taxpayers more than $1.4 billion.

Boeing, in a statement, said it is “proud to build the next generation of Air Force One, providing American Presidents with a flying White House at outstanding value to taxpayers.”

“President Trump negotiated a good deal on behalf of the American people,” they said.

The agreement includes the two 747-800 aircraft, and the cost of modifying the commercial planes with the equipment needed to support the president, including external stair, large galleys and a secure communications suite.

As an example of the unusually high costs associated with Air Force One, the Pentagon announced in December that Boeing was given a $23.7 million contract to design, make and install refrigerators for the president’s planes.

The White House said the deal would put Boeing on the hook for cost overruns. In 2011, Boeing agreed to a $4.9 billion fixed-price contract with the Air Force for a refueling tanker, the KC-46. Through late last year, cost overruns had reached about $2.9 billion in pretax costs.