WASHINGTON >> Defense Secretary James Mattis today ordered reviews of two key Air Force aircraft programs that have been criticized by President Donald Trump as too expensive.

Mattis asked Deputy Defense Secretary Robert Work to conduct a review of the F-35 Joint Strike Fighter program to find ways to “significantly reduce” the costs. He said the review should compare the F-35 with the F/A-18 Super Hornet and determine if an upgraded Hornet could be a cost-effective alternative that also meets requirements.

Mattis also asked for a review of the presidential aircraft program — known as Air Force One — to identify cost savings. Boeing is slated to build two new planes to replace the aging models that shuttle the president around the world. The new aircraft would go into service around 2024.

Mattis’ orders come after Trump’s tweets in December revealing that he asked Boeing to “price-out” a comparable Super Hornet became of cost overruns in Lockheed Martin’s F-35.

The stealthy F-35 has a nearly $400 billion price tag. Three versions for the Air Force, Marine Corps and Navy are being built, and other countries, including Israel, are buying the fighter jet.

Despite the huge cost, the program has strong bipartisan support in Congress, where lawmakers view the aircraft as essential to U.S. national security.

Trump also tweeted last month that the costs of the new Air Force One were “out of control.” He demanded: “Cancel order!”

Last March, the Government Accountability Office, the government’s auditing arm, estimated total program costs at more than $3.2 billion, much of it for research and development, through the 2020 federal budget year. The Defense Department and Air Force officials put the cost for two new aircraft at about $4 billion, when research and development, construction and future maintenance were included.

The Air Force has pressed for a faster replacement schedule, saying the aging current Boeing 747s are becoming too expensive to repair and keep in good flying shape.

While Mattis, Trump and the Pentagon can push for deep cuts or even try to cancel the program, Congress controls the government’s purse strings and makes final budget decisions.