President Trump makes no secret of his displeasure over the cost of renovating the Federal Reserve headquarters — around $2.5 billion, or even higher by the president’s accounting.

But getting the White House to discuss another of Washington’s expensive renovation projects, the cost of refurbishing a “free” Air Force One from Qatar, is quite another matter.

Officially, and conveniently, the price tag has been classified. But even by Washington standards, where “black budgets” are often used as an excuse to avoid revealing the cost of outdated spy satellites and lavish end-of-year parties, the techniques being used to hide the cost of Mr. Trump’s pet project are inventive.

Which may explain why no one wants to discuss a mysterious, $934 million transfer of funds from one of the Pentagon’s most over-budget, out-of-control projects — the modernization of America’s aging, ground-based nuclear missiles.

In recent weeks, congressional budget sleuths have come to think that amount, slipped into an obscure Pentagon document sent to Capitol Hill as a “transfer” to an unnamed classified project, almost certainly includes the renovation of the new, gold-adorned Air Force One that Mr. Trump desperately wants in the air before his term is over. (It is not clear if the entire transfer will be devoted to stripping the new Air Force One back to its airframe, but Air Force officials privately acknowledge dipping into nuclear modernization funds for the complex project.)

Qatar’s defense minister and Defense Secretary Pete Hegseth signed the final memorandum of understanding a few weeks ago, paving the way for the renovation to begin soon at a Texas facility known for secret technology projects. The document was reported earlier by The Washington Post.