As you've probably heard, Trump tweeted about Air Force One:
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!
On the face of it, it sounds reasonable. Over $4 billion is a lot for a single airplane. One would think they buy one for a lot less.
But, as usual, the devil is in the details, which Trump overlooks before opening his, eh, twitter account.

Per
PolitiFact, there are quite a few he missed.
For one, the program is for two Air Force One aircraft, not one. That way, while one is grounded for maintenance, the other will be on call.
Each basic aircraft only costs around $380 million dollars. The bulk of the costs are for upgrades. Little things that passenger aircraft don't need:
The plane must be able to refuel while flying, and the president and his staff need to have communications capabilities equivalent to what is in the Oval Office -- secure video conferences, classified computer access, and nuclear-strike controls. It also needs robust defensive systems such as missile evasion.
The new planes will be "both the fastest and longest commercial airliner in the world," according to military.com. They will be able to fly 7,730 nautical miles -- nearly 1,000 more than the current planes -- and will produce 16 tons less of carbon dioxide on a typical flight, according to the company.
I'm sure we could get some cut-rate electronics from another country, like China, but somehow I don't think Trump would do that.
And this $3.87 billion price tag (not more than $4 billion) is over a 12 year timespan. Because it will take time to assemble these custom aircrafts. And because the price tag includes research, development, testing and evaluation of the aircrafts and their components, along with maintenance, fuel and the cost of pilots.
The Defense Department will spend about $8.132 trillion on other projects during that time.

But the best part is, Trump
will not cancel the program. Because the current Air Force One jets are 26 years old, and they have an expected life of about 30 years. The President will need new AFOs by 2020, perhaps sooner.
So I don't see Trump feeling comfortable flying around in outdated aircraft with two-decade-old defensive technology while someone is likely to be wanting to shoot him down. Somehow I think he values his posterior a bit more than that.

Unfortunately, this is only a first of a long series, where Trump shoots his mouth off before knowing or considering all the facts. Let us hope they will stay as inconsequential as this.