The extremely thin GaAs cells from Alta Devices are flexible and even higher efficiency than monocrystalline silicon cells, with excellent power to mass ratio.

The extremely thin GaAs cells from Alta Devices are flexible and even higher efficiency than monocrystalline silicon cells, with excellent power to mass ratio. Multijunction inverted metamorphic cells are even higher efficiency and also offer excellent power-to-mass, over 1000 W/kg. They're probably still too expensive for a huge airship though. Even if it's a military airship.