A staple of the steampunk universe is the Airship. Dirigibles as they are commonly called (from the French (diriger to direct plus -ible), meaning "directable" or steerable) are blimps with open ship-like bases or enclosed Gondolas to hold passengers and/or cargo, and are directed by rudders and propellers, jet engines or even sails as opposed to Balloons which follow the wind with no control of their own.
How do they fit into the Steampunk genre? Truthfully they fit into the timeframe that Steampunk embodies more than they do the aesthetic of steampunk design. They are a symbol of freedom. In fact they are a symbol of the most freedom that one can achieve within the level of technology at the time. Not bound by the constraints of ground or ocean travel like a locomotive or steamship, but still slow enough that they harken back to the sea fairing days of pirates and privateers. In fact there are groups, troops and even rock bands that have dedicated their lives to the “Airship Pirate” lifestyle.
During this timeframe there were no grander or more highly embellished vehicles than ships. Often constructed from the finest materials and built by the most skilled artisans money could buy. Ships were more than possessions, they were characters. Often given names and adorned with figureheads depicting goddesses or mythical beasts, they really took on a life of their own. Far more important (and expensive) than even a car is today. They offered more than merely conveyance, they offered a lifestyle. Free as the wind and beholden to no one, a ship was a golden ticket to and from anywhere and anything that you pleased. That same spirit is embodied in the Airship to Steampunks.
The positive upshot of the Airship fascination is that the highly embellished nature of ships and machinery of the time gets translated into every object that steampunks build. Rather than settling for function alone, the emphasis centers more directly on form. Objects are not only built to serve function (often fictional functions) but they are decorative pieces of art in themselves. Steampunks take inspiration from every piece that goes into making a machine like a ship. From the rigging to the hull, every element of ship design has potential to inform the design of something else. I personally have always been fascinated by the intricate scrollwork and carving that would adorn every piece of railing or molding on a ships surface and the large expansive whale-like structure inside the hull that supports everything else. I also derive inspiration from the internal workings of steamships: dials, controls, levers, swing-arms, even reactors and cooling rods inside Nuclear Submarines are beautiful in their own way. All of these elements find a home in every piece of sculpture or jewelry I design.
I find it interesting that we now see a resurgence of Locomotives and Airships in many areas but especially in remote locations like Alaska where air and rail travel is the primary form of commerce. Airships are quiet, reliable and more efficient than small aircraft and require no more education than obtaining a drivers license. We have not (thankfully) seen a movement of air pirates but we may see something similar to a Privateer; private individuals that offer transport and protection for people or cargo, for a price of course.