[ano]

Yes, it is hard to get. That's why I said about being lucky. I don't rely on this, certainly. However, I think that air booster can be got when you really need it. Either from trade (Vanheim, Eriu and Caelum have A4 quite often) or from that rare crone, or at least you may empower for 60 gems. I consider this being quite real in the long run. Anyway, I think that having fast expansion, good combat pretender and very useful bless is more important than being sure you have A4 for air boosters, staff of storms and whatever else you need.