Thanks, tdracer and Etud_lAvia: there seems to be a difference of opinion here
Since there is no effective way to protect an aircraft from a fire in self-oxidising materials, it seems to be insane to allow bulk transport by air. I'd go so far as to ban their carriage in the hold at all, even in luggage. An individual laptop (or smartphone) battery could cause enough damage to seriously compromise a flight because they have tremendous energy density.