The Kosovo War:  In the spring of 1999, NATO engaged in a precedent-setting air campaign over Serbia and Kosovo known as Operation Allied Force (OAF). This event marked a milestone for airpower, as it was, arguably, the first time airpower alone was decisive in achieving victory in combat. By the end of the conflict, in June 1999, America and its allies had mounted a monumental effort to achieve the immediate goals of halting ethnic cleansing in Kosovo and providing for the return of hundreds of thousands of refugees. Ground forces, introduced following the end of the air campaign, have subsequently been employed to secure the peace. (Source: Air University Book A-10s Over Kosovo -- Marty McDonough was a contributor).