Airships require lift, propulsion and control of roll, pitch and yaw while maneuvering.
Balloons, blimps and dirigibles obtain lift by being lighter than air.
Balloons, of course, provide no propulsion and rely solely upon the winds for maneuvering.
Blimps are a form of dirigible which has no hard structure, but gains it shape from the pressure of the gasses within it. Most dirigibles, however, have a hard interior frame. Dirigibles provide a limited form of propulsion by using large, rotating fans, usually human-powered.
While many suggest maneuvering control might be improved with better propulsion, the lack of such a system, coupled with the success and availability of alternatives, render lighter-than-air craft to be little more than curiosities.
We will not discuss lighter-than-air ships further other than to mention the one notable exception to airships of this class. I am, of course, referring to Prince Filburd's Dragon Chariot. Many argue, however, than this device should not be considered an example of a successful lighter-than-air design since, while the dragon did, in fact, pull the blimp with remarkable speed and accuracy, it did also, at the conclusion of the maiden flight, consume Prince Filburd. As a result, while brilliantly conceived, the Dragon Chariot was largely considered impractical due to the lack of volunteers for follow-up research.
Summoning an air elemental is quite easy. Many aspiring mages are, in fact, self-taught; and all Mage Colleges include the practice as part of their introductory Summoning 101 courses.
Air Elemental are, however, quite capricious and hard to control; even more so if the mage is inexperienced. Most mages are quite capable of summoning and controlling an Air Elemental for a short while, maybe an hour or two for, say, for a quick jaunt across a valley to a nearby town. Only the most experienced mages have developed the strength of mind and singleness of purpose needed to control them for the days and weeks required for long distance travel.
For this reason most Airship lines using Air Elementals make frequent, short hops, much like stage coaches. Just as with stages, their Airships will stop every hour or two to change to a rested mage and a fresh Air Elemental. Lower-priced lines do not have a huge staff of mages and, often, each stop will last several hours while the mage rests and prepares for the next leg. Higher-priced lines follow much the same model, but shorten the layovers by having rested mages waiting at each stop along the way. How ever the line operates, travelers regularly complain about the frequent, long layovers. Such complaints are, of course, not without merit since, while a trans-continental trip could, theoretically, be completed in little over a day, the typical trip with a high-priced line takes nearly four days and, for the smallest, lower-priced lines, can take nearly three weeks.
This need for frequent stops makes inter-continental travel problematic, of course.
Attempts have been made to station barges as layover stops but, due to the difficulty of maintaining a fixed station, and considering the frequent losses due to weather (or, as some claim, the occasional Sea Serpent [even considering the fact that the lack of survivors makes such clams difficult to prove]), such attempts have largely been abandoned.
Nonetheless, inter-continental trips, while extremely expensive, are possible. The most common approach is to carry a staff of eight to twelve mages on-board. This, of course, severely limits the space and carrying capacity.
In addition to complaints about frequent stops, another common complaint among Air Element Airship travelers is the constant rolling and bobbing. For this reason, most Airships reserve the forward areas for passengers and relegate the rear to cargo. This unbalanced load, of course, increases the bobbing motion. To combat this, the line either packs more passengers into the forward areas, or severely limits the cargo. The most noticeable effect of the rolling and bobbing, however, is the wide rear railing, with loops of safety ropes, which most Airships feature. This problem has gave rise to the phrase "a real downwind passage," which has come to mean an extremely unpleasant event.
Occasionally, a truly great and powerful mage will arise who can be prevailed upon to undertake a long journey with an Air Elemental-powered Airship. Of course, should mages of sufficient power and experience exist, the wages demanded to entice them to interrupt their research and undertake a long and, probably, life-threatening trip mean that only the more wealthy nation states can even consider financing such an expedition.
There are few examples of long journeys by Air Elemental-powered Airships. Nearly everyone, though, will recall Tamelia Filburd-Earnard who, although completely inept at the magical arts, somehow became a close friend of an Air Elemental. Since Air Elementals have no know name in any known tongue, Tamelia took to calling her friend "Lucky Windy". The story (undocumented, but widely believed to be true) is she and her second cousin (thrice removed), Prince Filburd, were arguing about air ships and, to prove her point, Tamelia, with the assistance of Lucky, undertook an around-the-world trip. However it started, after making it over half way, the pair disappeared. Some say Lucky had had enough and simply abandoned Tamelia. Others say it was poor navigation and they went down in the ocean. But, by far, the most common theory is they were consumed by a Sea Serpent (but, as always, there were no survivors, so many dispute this).
By far the source of the fastest propulsion, the more reliable source of lift, and the finest maneuvering control comes from Lift Crystals.
These highly prized crystals form deep underground by as-yet-unknown processes. Finding them is complicated by the fact they are only found pressing hard against the roofs of large caverns; and, so, are often overlooked. Small crystals are relatively common (at least, in the caverns where crystals are found at all). This is mainly due to the brittle nature of Lift Crystals.
It is believed the largest Lift Crystals formed long ago, when the caverns were much smaller and, thus, formed against the roof. Later, crystals which may have been just as large were exposed by the slow erosion of the cavern but, when finally freed, flew into the roof with such force they shattered.
The greatest problem with Lift Crystals are their extreme cost. Some maintain the reason for the high prices are the Drawven monopoly of their mining.
Conceptually, mining List Crystals is not difficult. Once simply needs to snare the crystal, weigh it down until it floats, then simply push it through the air. For small crystals, this works well and huge quantities are easily obtained. This is complicated by the fact that the lift from a Lift Crystal increases with size. Truly large crystals can lift several thousand stone. Generally, pairs of lead ingots, connected by iron chains, are used to weigh down such crystals. But simply levering the crystal far enough down from the roof to place the chains can prove impossible.
Lift Crystals have two unique properties. By careful application and balancing of these properties a skilled handler can control the airship with amazing precision. These effects depend upon the size of the Crystal. Thus, the size of a List Crystal Airship is limited by its Crystals. The largest, most expensive Crystals are, in general, only used by the largest nation states.
When grouped close together, Lift Crystals can easily be pointed in any direction. When separated, a Crystal wants to hold direction. Airship designers use this property for stability and precise control of the airship's orientation. For example, to rotate left or right, one simply moves the "Z" Crystal away from the "X" and "Y" Crystals, locking the "Z" axis while allowing the ship free motion about the other two axes.
Applying an electric charge to a Lift Crystal causes it to move in the direction it is pointed. The greater the charge, the quicker the Crystal moves.
This later effect was only recently discovered. While the direction-holding properties of Crystals have been know for centuries, their reaction to electricity was not until discovered Hornbladder Filburd was riding upon a newly delivered 6000-stone Lift Crystal, parading it around Filburd Castle when a bolt of lightning struck the Crystal sending Hornbladder and his Crystal streaking off toward the horizon. The Crystal was never found (many suggest its speed exceeded escape velocity and it is now somewhere in inter-stellar space). Hornbladder's remains, however, were found several weeks later, some 11 Leagues distant, by an Elvish Hunter.
This brief introduction into the basics of Airships and their history has been brought to you by Filburd Airships. Purveyors of the best-built Airships on the planet for both commercial and military use.
Remember, "Nothing flies like a Filburd!"
I forked real life and now I'm getting merge conflicts.