If I recall correctly, you do want a bit of air if you're going for aging. The oxygen left in the jar is required for aerobic fermentation, and once that is depleted the jar goes into anaerobic fermentation. Less air then would slow down the aging process?
Greg Pease has an article over in the pipesmagazine site that gets into this. Also, I found C&D's post interesting.
http://www.cornellanddiehl.com/the-l...ails.cfm?id=17