A lot of the complication is reduced by the fact that modern air to air missiles have 100+ mile ranges (so you don't need a traditional intercept). You also don't need 100% coverage. Rather than covering all of Ukraine 24/7, you only need to cover an unpredictable part of it such that flying is risky everywhere. Getting basing in Poland (or Keiv) would obviously help reduce the flight time and awacs amount needed.

To be clear, I'm not saying it would be politically easy or low risk. It would almost certainly result in a couple fighter planes being shot down.