Joni -
Don't know what kind of YARN you are refering to ??
I do normally start out with a small drop or two of Aquel before I start fishing the poly yarn indicators pictured, but have fished the same indicator for hours without adding any. If they do tend to bog down, a couple false casts normally brings them back to full floatation. Seems to me they are no more "air resistant" than a dry fly or hopper big enough to do the same job.
John