Both sides, Putin and Ukraine, NATO need to come to an accommodation that both sides can accept and still save face. Otherwise, they would be at war for years. In the end, each side does not get all they want. Give a little, take a little. That is what needs to happen. Escalation like establishing a no fly zone, goading Ukraine to keep fighting, probably, is not the best way to end this war. Women and children will suffer the most. Putin probably, will accept something he can spin as a win. Give him Crimea and the Donbass, Luhansk areas. Ukraine declares neutrality. NATO removes all tactical nuclear weapons from Estonia, Latvia, Poland and moves it further away. That buffer with Russia, Putin can take that as a win and pull his forces out of Ukraine. It will also, save a lot of lives of Ukrainians and Russians military and the civilian population.