When I sift, I use a screen sieve, but I don't usually sift unless I feel the need to thoroughly mix the dry ingredients. What I do is weigh rather than depend on volume.
1 cup of flour is supposed to weigh 5 ounces. Unsifted flour here in arid Colorado comes out of my big glass flour canister dead on - I've weighed it several times just to test. It also tells me that my cheapo tin measuring cups are accurate, something I was a bit surprised to find out. I suppose that in a more humid environment, a cup might weigh a bit more. Sifted flour should be a bit lighter, but I've never tested it.