I was looking at the FAQ on the Lallemand Yeast Co. (They make Danstar Nottingham, Winsdor, dry yeast) website and they answer an aeration question saying no need to do so. Very interesting answer. Here is the question and their answer:
Q: "I always aerate my wort when using liquid yeast. Do I need to aerate the wort before pitching dry yeast?"
A: "No, there is no need to aerate the wort but it does not harm the yeast either. During its aerobic production, dry yeast accumulates sufficient amounts of unsaturated fatty acids and sterols to produce enough biomass in the first stage of fermentation. The only reason to aerate the wort when using wet yeast is to provide the yeast with oxygen so that it can produce sterols and unsaturated fatty acids which are important parts of the cell membrane and therefore essential for biomass production.
If the slurry from dry yeast fermentation is re-pitched from one batch of beer to another, the wort has to be aerated as with any liquid yeast."
Q: "I always aerate my wort when using liquid yeast. Do I need to aerate the wort before pitching dry yeast?"
A: "No, there is no need to aerate the wort but it does not harm the yeast either. During its aerobic production, dry yeast accumulates sufficient amounts of unsaturated fatty acids and sterols to produce enough biomass in the first stage of fermentation. The only reason to aerate the wort when using wet yeast is to provide the yeast with oxygen so that it can produce sterols and unsaturated fatty acids which are important parts of the cell membrane and therefore essential for biomass production.
If the slurry from dry yeast fermentation is re-pitched from one batch of beer to another, the wort has to be aerated as with any liquid yeast."