Members of the 435th Contingency Response Squadron assessed runway surfaces, glideslope obstructions, and firing capes, according to an Air Force release.
Jan Mayen is north of Iceland and between Greenland and Norway, the latter of which administers and supplies it with regular flights by C-130 aircraft.
It has been used for centuries for whaling, hunting, and, more recently, meteorological monitoring. During the Cold War, it was used as a base for communications and navigation systems. Though it doesn't have a usable port, its airfield can be used for research and search and rescue.
The island is also above the Arctic Circle and, the release notes, "along sea-routes connecting Russia to the Atlantic Ocean."