RAF Fylingdales is manned by the RAF but mostly owned by the USAF and from my time there in the 1990s some of the RAF Officers sported USAF Radar Officers or sensor Opertors wings. Think it is a local thing to cheer the Radar folks up.
link to piccys of USAF Wings and things so you may see the wings you spotted.
Badges of the United States Air Force - Wikipedia, the free encyclopedia
They even have Stackers Wings (Supply and Fuels)