It seems surprising to me that there is not more information on the website regarding what gas this gas-filled lenticular-shaped aerostat thing is floating with. I understand they are aerostatic and the gas needs to be lighter than air, but that doesn't leave many options that are not helium I guess. And then in order to drop whatever they haul down, they'll need to either let it escape or contain it somewhere else, or spend energy at keeping it down somehow.
