Donald Trump is mad at Boeing, but what else is new? On Tuesday, the president-elect tweeted that he was considering canceling the Chicago-based aerospace company’s contract to build the new Air Force One because it was too expensive.

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! — Donald J. Trump (@realDonaldTrump) December 6, 2016

Enough ink has been spilled trying to suss out Trump’s motivations in this latest Twitter beef — He wants to protect taxpayers! He wanted revenge for a comment by Boeing’s CEO about free trade! He’s dangerously unhinged and someone needs to take his phone away, for the love of god! — but we thought it was worth looking into why Boeing was charging the federal government so much money to build a couple of big-ass jets.

First of all, the current Air Force One, a Boeing 747-200B, is over two decades old and needs to be replaced. Last year, the government signed an eight-year, $3 billion contract with Boeing to replace the current aircraft. Built on the frame of a Boeing 747-8, the new Air Force One will be bigger, more powerful, and able to fly farther than the current plane.

But more than that, the new Air Force One will be the most resilient, high-tech, tricked-out jumbo jet in existence. Just ask CNN’s aviation editor John Ostrower.

When you have to harden two 747s to withstand an electromagnetic blast from a nuclear explosion, the price tag is high. — Jon Ostrower (@jonostrower) December 6, 2016

Air Force One runs on 165,000 pounds of state-of-the-art electronics and is protected by both an electromagnetic pulse shield and a radiation shield in the event of a nuclear blast.

Capable of withstanding an electromagnetic blast? Check. Capable of midair refueling? Check. Capable of dodging heat-seeking missiles? Check. There really shouldn’t be any questions about the costs of building this incredibly state-of-the-art plane, and yet here we are.

Less CO2 emissions for a climate-change-denying president

Despite its size, the modified 747 can fly for days without refueling. And it can reach speeds of up to 620 mph, 40 mph faster than its commercial counterparts. Also, the new Air Force One will be greener than the current one: Boeing says the 747-8 emits 16 less tons of CO2 per trip than the 747-200B. Not that this particular point matters much to a president-elect who denies the existence of climate change.

Asked by reporters to clarify his tweet, Trump said, “Well the plane is totally out of control. It's going to be over $4 billion for [the] Air Force One program. And I think it's ridiculous. I think Boeing is doing a little bit of a number. We want Boeing to make a lot of money, but not that much money."

“We want Boeing to make a lot of money, but not that much money.”

Ignoring the fact that Trump said he doesn’t want an American company that employs almost 157,000 people to make “that much money,” the fact that he thinks “$4 billion” is too steep of a price tag is a head scratcher. The planes themselves aren’t that expensive, around $225 million each. But it’s the costs associated with building a resilient enough aircraft to protect the president, as well as one that can act as a mobile command center like it did during 9/11, that accounts for bulk of the expense. The Pentagon is budgeting $3.2 billion for research and development, military construction, and acquisition of at least two new Air Force One planes through fiscal 2021, an analyst told Bloomberg.

According to CNN Money, the Air Force hasn’t even told Boeing whether it wants to buy two or three planes. Boeing’s current contract is only for $170 million, but many details about the overall replacement project, such as how much of the aforementioned countermeasures and security specs will be included, is still in flux.

“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 responding to Trump’s broadsides. “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.”

Of course, Air Force One doesn’t have everything. It certainly lacks the splashy, gold-plated fixtures found in Trump’s own private jet. Which certainly raises the question of whether the president-elect’s tirade against Boeing is a smoke screen for his effort to get his own Boeing 757 designated as the official presidential aircraft. Wouldn’t want to let all that gold go to waste.