I'll speak as air force aircrew.
I will preface this as I am no fan of Trump whatsoever, but this Scotland resort thing is nothing but a witch hunt by Democrats.
The big things that they are claiming are "controversial" are that 1: a C-17 stopped for gas at Prestwick, Scotland and 2: The crew went to crew rest at a Trump Resort.
Air Force cargo planes stop at Prestwick, Scotland for fuel or crew rest all the time, even before Trump decided he wanted to be president. It all depends on what cargo the plane is holding, the route of flight, and availability for parking spots. If Ramstain Air Base or Rota Spain where we usually stop are taken, then we go to Prestwick.
The news article I read claims that the Pentagon puts crews up at inexpensive lodging selected by midlevel officers. That couldn't be further from the truth.
When a crew gets to the destination, it is up to the crew to figure out where to stay if there is no US military lodging. They can stay wherever they want as long as the cost is under the Per Diem for that area. If the crew decides to stay at a more expensive place, they have to pay the difference out of their own pocket.
The Guard crew in this story decided to stay at a Trump resort, and probably paid out of pocket for staying there. Simple as that. You have to remember that these guys are either airline pilots or professionals flying for the Air National Guard as basically a side gig. They more than likely had the money to pay out of pocket to stay at the Trump resort and decided to do so without the endorsement of the Trump administration.
This is a non-story.