On Tuesday, President-elect Donald Trump tweeted that Boeing’s Air Force One contract should be canceled, citing costs.

“Boeing is building a brand new 747 Air Force One for future presidents, but costs are out of control, more than $4 billion,” Trump tweeted.

Hours later, Boeing said its CEO spoke with Trump and was committed to controlling the costs of the aircraft.

“We are currently under contract for $170 million to help determine the capabilities of these complex military aircraft that serve the unique requirements of the President of the United States,” Boeing said in a statement. “We look forward to working with the U.S. Air Force on subsequent phases of the program allowing us to deliver the best planes for the president at the best value for the American taxpayer.”

The Air Force plans to replace the two 747-200s that serve as the presidential Air Force One fleet with its 747-8. According to Boeing's website, the 747-8 is the fastest commercial jet in the world, with a cruise speed of Mach .855. It's also 18 feet, 4 inches longer.