Do you hear airport noise in greenhills/ millwood neighborhood?

You will definitely get some airport noise in Millbrae though I can't speak specifically to particular neighborhoods. I'm not sure if it is overwhelming--I suspect it just depends on how sensitive you are to noise in general.

Daly City is nice too, a little less expensive than Millbrae probably and closer to SF, though Millbrae is a little nicer and I think it has better schools. Anyway, good luck.