While most folks think of the era of flight as starting in 1903 with the Wright Brothers, they forget that humans have been flying in lighter-than-air craft for over two hundred years. For the first several decades, these were confined to hot-air balloons, but by 1850, a Frenchman named Pierre Jullien devised the first powered dirigible using a wound-spring clock work motor. Fifty years after that, the German Count Ferdinand von Zeppelin built his first rigid-frame airship of a type that would bomb London during the First World War and go on to carry passengers until 1937.

The age of the commercial, passenger-carrying airship came to an end when the Hindenburg exploded while docking at Hazelhurst, New Jersey. The cause was the gas used for lift - extremely flammable hydrogen. Meanwhile, the U.S. military - fortunate in having a nearly inexhaustible supply of an inert alternative, helium - continued using airships for a time. Such craft are still used for commercial promotions by a certain tire company, who flies their famous blimp over major sporting events.

Today, with the fossil fuel source of jet fuel quickly running out and highways so jammed with vehicles no-one can move, both the military and commercial enterprise are taking a new look at an old concept.

While incapable of the speeds achieved by powered, heavier-than-air craft, blimps and dirigibles are far more stable in bad weather. Among other applications under consideration are the uses of high-altitude (40,000 meters/120,000 ft.) airships as platforms for space telescopes, observatories and surveillance equipment. At least one "hybrid" design that uses stubby wings for lift is being tested as a freight carrying alternative to trucks, while at least one company - Aeros - is planning to bring back the era of airship travel with an 850 foot-long luxury liner capable of ferrying 200 passengers. One enterprising Frenchman has come up with a single-passenger model, and NASA has even proposed one design that can be carried to other planets, inflated, and piloted  remotely for exploration

Below are several proposed designs we may be seeing in the skies before too much longer.