This seems to be a common mis perception. Neither the Iraq no fly zones nor the war in Kosovo were authorized by the UN. In fact the UN Sec.General
opposed the no fly zones. Given my choice between making the UN happy, and saving the lives of thousands of Kurds, who flourished under the protection of the non fly zone between 92-2003, I am going to go with the Kurds. Right now both Britain and France are calling for No Fly zone.
The situation in Kosovo was particularly tragic, we spent weeks vainly attempting to get Russia to not veto a UN resolution, while Milosevic and his thugs were killing thousand and raping tens of thousands. Ultimately, the war was fought as NATO operation. However, it was in reality it was a US operation with more than 95% of combat mission being flown by US aircraft. Acting sooner would have saved thousands.