Exercise Frisian FlagIs a major NATO multinational aerial exercise, held annually at Leeuwarden Air Base, Netherlands, over the North Sea and in the skies above the Netherlands, Germany and Denmark. Missions flown during Frisian Flag included defensive and offensive air missions, protection of friendly aircraft and Close Air Support (CAS) strikes. Some missions call for Forward Air Controller units coordinate with fighter elements to attack ground targets. Surface-to-air missile systems enabled realistic exercise scenarios missions.