Maybe its just political.
Maybe no NATO member bordering Ukraine wants warplanes taking off from their airfields and heading into a war zone. And I don't blame them. Even Poland didn't want them going directly to Ukraine from their bases.
Its awfully easy for US to talk about "no fly zones" when its someone else who'll have to take the heat for it if it goes south. All this "no fly" talk
really steams me. If we don't want to do it, how can we expect anyone else to get involved?