Dextroluma transportation is quite advanced.  Before contact with other species had been established, they had already constructed advanced spacecraft capable of faster than light (FTL) travel.

Spacecraft are not the only form of transportation available on Aerius, of course.  There are planet to space transport ships that travel routinely between many cities (although not underwater ones) on Aerius to Galactica, but there are other forms of transit for traveling between the nations within Aerius’ atmosphere.  Some Dextroluma can make the trip to Galactica under their own power, generally those who have a genetic background linked to hyperspace.  Most would rather travel in spacecraft, however - it’s a good deal more comfortable.

Several other nations have specialized methods for traveling to them.

The Crystal Isles use crystal teleporters for most entries.  The teleporters are a blend of magic and science, but allow those with crystal horns or a specially issued crystal token to teleport directly to the Crystal Isles.  Dextroluma with a genetic background of air, delta, or hyperspace may be able to reach the Crystal Isles under their own power, but that typically requires far too much math to accurately predict the position of the Isles to be worth doing.  Most major cities have plenty of teleporters for travel to and from the Crystal Isles, after all, and even some smaller towns have them.

The Arcane Artifice, despite facing a similar issue with how it rotates the planet, simply constructed a number of shuttles suitable for use on the planet that complete routes along the same lines as the Galactica spacecraft.  They simply input devices on their shuttles that communicate to a controller’s network and remotely guide the shuttles back to their landing bays.  Like Galactica’s spacecraft, their shuttles are unable to descend underwater.

Lunaris and Solaris each only experience travel once per turn of the planet, roughly at midnight time and noon in the Sky Barrier when they pass by the town of Cirrus.  While it is hypothetically possible to travel to them otherwise, the only individuals who typically bypass that constraint are traveling between them and the Crystal Isles.  Any other method would, after all, require a lot more math than most individuals would consider worthwhile.  (Even routes from Galactica and the Arcane Artifice typically arrive on Lunaris and Solaris during these times!)

The Realm of Tides has both underwater areas and above water areas.  Travel to the above water areas can be done any of the ways listed above, by boat, or even by Draphibian - although those need rest along the way if used.  Travel to the underwater parts of the Realm of Tides can usually be done by swimming, by Draphibian, or by ‘capsule’, which is essentially akin to a submarine meant for individual travel and is powered by the movement of water.  (Of course, there are always the crystal teleporters too for those who can use them).

Travel to the Eternal Depths is quite infrequent, not so much because of being underwater as due to the immense pressure.  Anyone traveling to or from the Eternal Depths has to spend a certain amount of time simply learning to acclimate to different levels of pressure, and any travel has to be done gradually.  Those who are able to manage it can travel by swimming, by Draphibian, or via a larger version of the capsule that is pressurized specifically for travel to the Eternal Depths.  (This form of capsule can only be rented or purchased in a few parts of the Realm of Tides).  Even travel by crystal teleporters is limited, as visitors who use those must appear in rooms pressurized to match the Crystal Isles and then spend time traveling through a series of waiting rooms that help them gradually acclimate to the pressure of the Eternal Depths.

The sole exception in the Eternal Depths is The Dome, which is pressurized to the ‘sea level’ of Aerius.  Those who teleport from the crystal teleporters to there are generally able to do so easily, and visitors traveling by capsule can forego needing the gradual pressurization of their capsules, so long as they make certain to get one that is capable of withstanding the pressure of the Depths on its hull.

Travel to the surface nations is simpler, other than to the Blighted Wilds.  All the above methods are viable, and plenty besides them as well.  While there is not large-scale above-ground infrastructure between cities/towns/villages for things like trains or cars that require a road to drive on, there are certainly other options.  Most nations that border each other have some form of underground subway, as well as shuttles that travel in the air between them.  Individuals sometimes have personal vehicles of all sorts meant for ground travel off road, and some may even have personal vehicles meant for air travel at lower altitudes than shuttles.  And of course - there’s always walking or riding a Draphibian, though of course that makes for a much longer trip.  Within cities, towns, and villages, there are typically roads and sometimes even railways, depending on the environment.  It’s not unusual to see Draphibian-drawn carriages in some cities, as they are still favored by some wealthy Dextroluma as a sign of their wealth.

The Blighted Wilds is typically only traveled to via wooden ship.  It is an odd choice to some, given that wooden ships are seen as an old and somewhat outdated form of transportation, however, it was by decree of Queen Iola after the attack on the Crystal Isles that anything more modern be kept away from the Wilds as much as possible.  There are a few spacecraft that hover over the Wilds to surveil it from a distance, though, but they have strict instructions to not go over the land and to try to direct any crashes into the Realm of Tides…