Glasgow Prestwick Airport - USAF
As well as hosting a Canadian Air Force detachment (https://www.olliehillaviationphotography.co.uk/l/canadian-forces-base-prestwick/), Prestwick Airport also hosts transiting aircraft from multiple other nations.
The United States Air Force are regular visitors to Prestwick, with C-17s seeming the most common among the Ayr skyscape, as seen below.
United States Special Operations Command Dash 8 N8200R FATMAN12
Boeing C-17A Globemaster III 02-1098 RCH831 - 305th/514th Air Mobility Wing - Joint Base McGuire-Dix-Lakehurst
Boeing C-17A Globemaster III 02-1109 RCH269 - 62nd/446th Airlift Wing - Joint Base Lewis-McChord
Boeing C-17A Globemaster III 07-7172 RCH557 - 60th/349th Air Mobility Wing - Travis Air Force Base
Boeing C-17A Globemaster III 99-0168 RCH811 - 517th Airlift Squadron - 3rd Wing - Joint Base Elmendorf-Richardson
Gulfstream C-37A 01-0029 VALOR29 - 76th Airlift Squadron - 86th Airlift Wing - Ramstein Air Base
Learjet C-21A 84-0096 VALOR21 - 76th Airlift Squadron - 86th Airlift Wing - Ramstein Air Base