Donald Trump's helicopter got to Scotland via airlift by US Air Force cargo planes. Specifically, the VH-3D Sea King helicopters, known as "Marine One" when carrying the president, were flown into Scotland using US Air Force C-17 Globemaster cargo planes. These helicopters were part of a larger security and travel operation that included motorcades and other aircraft. Upon arriving in Scotland, Trump used Marine One to travel between locations, such as moving from his golf resort to the airfields before departing Scotland.
In summary, the helicopter did not simply fly over from the US but was transported by military cargo aircraft to Scotland to support the president's visit and movements within the country.