The United States owns two (just two) operational Air Force 1s. They are Boeing 747's with a fancy paint job, and every imaginable electronic device and defensive system. Cost was no object back then. The primary reason for Air Force 1 is to impress everybody in the world. We are the only country rich enough to furnish a custom widebody jet liner to fly the president around. All the other heads of state fly commercial. The current two aircraft have been flying since the 1970's if memory serves, and you can make a case that it's time to replace them.
On the other hand, aircraft last forever. Every thing that wears out gets replaced. Maintenance (I used to be a maintenance officer) has to fix everything, soon as it breaks. If it ain't fixed, the crew won't accept the aircraft, causing all sorts of bad things, late departures, late arrivals, nasty phone calls, the works. Engines and other machinery have to to replaced every so many hours. So after 25 years of service, the current two Air Force 1s are as sound as when they left the factory, maybe better.
Somehow during the Obama administration, the Air Force got funding to buy two replacements. The new birds will be the same Boeing 747s with a sticker price of $352 million, each. That would accomplish the primary mission of Air Force 1, namely to impress everybody. Throw in some bucks for the fancy paint job. Let the passengers communicate with their smart phones.
That's not gonna fly in the Air Force I remember. I'm sure the Air Force contract calls for installing all the fancy electronics that the current models have, plus a bunch of new stuff that's been invented in the last 25 years. And thousands of hours of flight testing, of a highly reliable airliner that has been flying for nearly 60 years. Maybe the Air Force will pull the KC-46 tanker cost enhancement trick, demanding all the aircraft wiring be redesigned and rerouted "to meet Air Force standards". Boeing knows as much or more than the Air Force about the right way to wire an aircraft. What with one frill or another, the price tag is up to $4 billion for two aircraft. Which is too damn much.
With a bit more pressure from The Donald, they might be able to reduce the fancy electronics load and cost. I'm sure there is a bunch of stuff that the plane could jolly well do without. Or, just cancel the whole project and keep on flying the current, very safe, very impressive aircraft.