I don't seem to be able to dig up the source - was it Stratfor? or Foreign Policy? - but there's an opinion that the ground invasion was bound to split NATO. It gained credibility only because former prime minister of Russia went to Serbia and persuaded Milo that the threat was real.

In this way, Eltsin's Russia provided its last (but priceless, if you are looking from certain quarters) service to the West (again, suitably defined). The mighty irony is, of course, that the current groundswell of patriotism in Russia started from anti-American and anti-Western sentiments born during the Kosovo campaign.

And yes, "planes over Belgrade" was a figure of speech. They were part of the military operation which, among other goals, included bombing of civilian targets in Belgrade (yes, I know, propaganda TV tower and Chinese embassy which presumably collected intelligence and passed it on to the Serbs). Still, they were providing military services. There isn't even the weakest of excuses the Czech Republic used (CR sent a field hospital plus military police to Kuwait and later to Iraqi south; as a result, local politicians claimed that CR isn't part of the "coalition of the willing". The USA included it in their coalition list anyway).