The giant airships that could carry 66 tonnes

The airship could be set to quite literally make a big comeback. In 2013, the Aeros Corporation, based near San Diego, demonstrated a tethered flight of Dragon Dream - an airship measuring 90m (295ft) long and 27m wide.

As big as this airship is, it is still only small sized prototype - the final design could be more than 169m long and be able to carry a cargo of 66 tonnes.

BBC Click's Spencer Kelly finds out how the airship has the commercial potential of becoming a very efficient way of transporting heavy cargo.

More at BBC.com/Click and @BBCClick.