Late last month, President Donald Trump sent out a volley of social media posts and statements critiquing Boeing for its failure to deliver a new Air Force One. The latest iteration of the storied presidential "flying fortress" was supposed to take to the skies in 2024, but a bumbling series of delays, miscalculations, and missteps have pushed that date back. The setbacks reportedly forced Boeing to absorb more than $2.5 billion losses for a project with an initial price tag of $3.9 billion.

Aviation experts speaking with Popular Science blamed the mounting delays largely on poor corporate management at Boeing and potentially unrealistic expectations laid out by the first Trump administration when it agreed to the contract in 2018. But making Air Force One isn't for the faint of heart. The one-of-a-kind vehicle is built to withstand a nuclear blast and serve as a mobile White House during times of war. As former US News & World Report White House Correspondent Kenneth Walsh explains in his book Air Force One, the president's modified 747 jumbo jet is "quite possibly the most unusual plane ever built." 

Here's why Air Force One takes so long to build. 

What makes Air Force One different?

From the outside, the president's plane doesn't look all that different from a commercial 747 jet, save the large "United States of America" text stretching along its side. The real differences are under the hood. 

Aviation expert and American Enterprise Institute Senior Fellow Todd Harrison says the jet is equipped with advanced encryption capabilities that enable prolonged, secure communications from anywhere in the world. Additionally, the plane has shielding over every bit of its wiring and electronics to protect it from a potential electromagnetic pulse, such as one caused by a nuclear weapon. The plane also has "state of the art" navigation systems and a self-contained baggage loader. Though it does not have offensive weapons capabilities, Harrison says the plane is outfitted with defensive countermeasures that can intercept Stingers or other portable missile systems. There's no evidence these countermeasures have ever been used. 

"It's one of those things where you are 99% sure you'll never need to use [defensive capabilities], but in the moment you did, it would be worth every penny," Harrison said.

Air Force One also looks remarkably different from a commercial airliner on the inside. As Walsh recounts in his book, the plane's interior features far more plush and spacious accommodations than a commercial equivalent. The presidential suite alone reportedly includes a large desk and two couches that can be converted into beds. According to Walsh, the current 747 model comfortably accommodates two pilots, a navigator, a flight engineer, 26 crew members, and 76 passengers. It's also capable of mid-air refueling, meaning the mobile command center—which ordinarily has a maximum range of around 9,000 miles—could theoretically stay in the air for days at a time with proper refueling.