HG2 is a much more preferable battery for the AA ,than the Panasonic NCR.
HG2 might have less juice ,but it's much more safer (high current output ) than the Panasonic NCR.
I suspect that goes same for the AA 2 .
Personally I've used HG2 on my Air ,since I bought it.
Never had an issue.
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To answer to another member's question, who asked about the material of the Air's body(case).
It's not aluminium but
anodised stainless steel.
Probably same goes for AA 2.
Just remember to lightly grease the threads of the battery cap ,from time to time,
if you change batteries oftenly .
Use non-toxic teflon based grease (used on bicycles ).
http://www.chainreactioncycles.com/gr/en/finish-line-teflon-grease/rp-prod980