A California company called Aeros claims to have solved the central problem on zeppelin travel, which is the difficulty of maintaining stability while expending fuel (thus lightening the zeppelin as one travels):
"Modern airship designs deal with this by employing non-rigid hulls, multi-lobed hulls containing different gases, taking on water ballast at cargo unloading docks, and so on. But Aeros uses a compression system instead, called Control of Static Heaviness (COSH). It involves a rigid airframe and a membrane containing helium gas."
Predictably, the military is interested in Aeros' technology, but it could later be used for hauling freight or passengers.