A U.S. military air crew had a pair of sleepovers at President Donald Trump’s luxury golf resort in Scotland early this year — a pit stop so unusual the House Oversight Committee has been quietly investigating it since April.

But the Trump Administration has been stonewalling all requests for information, Democrats say.

“The Defense Department has not produced a single document in this investigation,” a top committee aide told Politico Friday.

The overnights at Trump’s Turnberry resort outside Glasgow, Scotland involved an Air National Guard crew using a C-17 military transport plane to ferry supplies to Kuwait.

On other trips to the region, the plane made stopovers at or near U.S. air bases in Germany, Spain, and Italy — but the Glasgow area has no U.S. military facilities.

House Democrats accuse Trump of illicitly profiting from government use of his properties — including Vice President Mike Pence’s stay at Trump’s property in Doonbeg, Ireland last month.

In 2018, the U.S. State Department paid the Turnberry property $77,000 for hotel rooms during Trump’s July stay at the resort.