Someone Might Want To Do Some Fact Checking

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

Edit: The only contract currently in place is for $170 million. Granted, that's for the planning phase. But someone tell me where the "more that $4 billion" figure came from. And the contract is for two planes, not one.