Yeah, charging them in the plane isn't the smartest option.

I've been using lipo rx packs in a couple planes, with regulator, and am pretty happy with them. If I was to switch to say the A123 packs, I'd have to buy another charger so I stick with the lipo for now. None of the three charges I have already will do the new technology batteries like A123. Set the plane up so you can easily remove the battery to charge.