Sneppelins

Sneppelins are identical in looks and purpose to Zeppelins, as they were created for that role, but they are however completely different in engineering. The Snell Zeppelin Company created their first prototype in 2122 following research into making Zeppelins more affordable through requiring less Helium. The breakthrough with the Sneppelin was that it doesn't require any gas at all, giving it more lifting power than even the Hydrogen Zeppelins.

Displacement (Physics)

All ballons are naturally in a pressure balance with the outside environment. Ballons that rise are powered by gravity, (the same as why ships float), where gravity pulls on all things equally. As a light gas such as helium is less dense than the air around it, when the same volumes of gas are present (i.e. equal pressure), the helium is pulled down by gravity less than the air around it is. As the air has had a greater pull per unit of air space, and flows as a gas, it displaces lighter helium gas around it. The same effect is acheived by heating the air in a hot air ballon, where the energy in the gas causes it to expand, effectively lowering the density relative to the surrounding air.

Sneppelin Engineering

Sneppelins are made from a fabric of carbon nanotubes woven into a diamond cross pattern that solidifies in a slight curve when under compression. A woven Sneppelin that is open to the atmosphere remains a floppy fabric like a Zeppelin. Ironically, you have to deflate it to 'blow it up'. As air is pumped out the fabric compresses down and forms in a way that has similar structural properties as a diamond. Once deflated the Sneppelin takes on the properties of an inflated Zeppelin, which causes much confusion on what terminology to use. For consistency and due to habit, a floating Sneppelin is considered to be inflated, despite the insides actually being a vacuum.

Shipping Boom

As Sneppelins don't require expensive and rare helium, and have more lifting power, Snepplins became a real option in shipping over land where there isn't transport infrastructure. By 2215 the Snell Zeppelin Company has 18% of Earth's shipping market and is the third largest shipping company.

One of the major shipping sectors dominated by the Snell Zeppelin Company is deorbiting. As the Snepplins are already a vacuum, they operate very effectively in the upper atmosphere and even a controlled fall from space. Snepplins are also used for high atmosphere pseudo-satellites.

General Notes

Hydrogen and helium cannot be kept by Earth as a gas. Earth's atmosphere displaces the two gases to the very top, where they are no longer of significant mass enough to be pulled by Earth's gravity. From here they drift into space.
Hydrogen is the lightest element but is highly reactive. It tends to have reacted into a heavier molecule before it drifts out into space. Also it is available in vast quantities having reacted with oxygen to make water.
Helium is a noble gas, as it keeps two electrons in a stable shell and so it doesn't react with anything unless you seriously and violently poke it. It is (near enough) twice the weight of hydrogen so doesn't have the same lifting power, but it won't catch fire. For that reason, helium is preferred choice of gas for Zeppelins.
Helium is difficult to store as it is smaller than all the atoms except hydrogen. An iron container must not have any gaps between the iron atoms that are larger than the helium atom. Total storage is difficult if not impossible to achieve, so almost all storage accepts that helium will slowly escape. Helium ballons leek this way which is why they slowly deflate over days. Hydrogen is easily stored as water.
As it is difficult for anything to keep it, helium is not easily available.
In 1903, oil drilling in Kansas produced a gas geyser that would not burn. America had discovered a source of helium and for a long while, was one of the countries with access to helium. Seeing Germany as a threat, America banned the export of helium to Germany to try to shut down their Zeppelin industry. With the choice of hydrogen Zeppelins or nothing, Germany chose hydrogen Zeppelins, which ultimately led to the horror of the Hindenburg disaster. Despite Zeppelins being very effective, this disaster turned people away from Zeppelins as a mode of transport.