The Serbs have more forces on the ground in Kosovo than most Americans seem to realize: 34 thousand or so well-trained regular army troops and police militia units. The regular army units have an estimated 300 tanks, plus armed personnel carriers and considerable artillery.
A sustained air campaign may be able to pretty much annihilate this ground force. But it will take time to know - 3 to 4 weeks of intense aerial attacks, at a minimum. And much of that, especially in the later stages, would have to be close air assault. That means likely loss of at least some U.S. aircraft.
About the Serbs' loss of two MiGs today: apparently Serbian dictator Milosevic felt there was a chance that the U.S. military might be so busy with its air campaign elsewhere, that a MiG or two might slip through and succeed in attacking U.S. troops in Bosnia. His hope was to create some chaos, spread concern and, perhaps, widen the war - thus hastening splits among NATO nations. It didn't work. Each time the Serbs send up MiGs, they get shot down. The total now is five.
On the diplomatic front, the Greeks and the Italians already are causing trouble with NATO unity. The White House is more concerned about this than they may let on.
There will be some letup in air attacks over the weekend. Bad weather will be blamed. Belgrade, the Serb capital, is expected to have its outskirts hit especially hard Friday night.