After all, most drones would not be able to last the half hour mark even when they have a full charge on them, but with the Hycopter, we are looking at 4-hour flight times, now how about that? The intelligent design involved in the Hycopter would allow it to stash 120 grams (4.2 oz) of hydrogen gas at 350 bar (5,076 psi) in its current structural tubing, and this means that there would be no need for any kind of separate canister.
The refillable tubes will eventually be made from polymer-lined 5 mm-thick carbon fiber tubing as opposed to clear acrylic that is part of the pictured display model. It is touted that that amount of hydrogen ought to be able to deliver a similar amount of energy as 3 kg (6.6 lb) of lithium batteries. [Product Page]