People need to get around, whether it's through the ghetto after dark or from one side of a planet to the next. While space ships are good for long distance, they aren't equipped to just dock or land anywhere.
Smaller vehicles such as cars, trucks, bikes or ATVs are powered by internal combustion engine that run on bio-ethanol, produced from agricultural wastes, as petroleum is not available in the system for obvious reasons. Novus also produces lines of entirely electrical powered vehicles.
Larger vehicles such as Space fighter or walkers are powered by miniature fusion engines.
The popularity of ground transports have not waned in the days after the exodus. Motorcycles and compact cars are well in use within cities while outer colonies favor ATVs and 4x4. Many vehicles are also designed to offer airtight seal and environment control for life on the non-terraformed colonies.
Tanks, artillery and armored personnel carriers are also still in operation with the military, while often rudimentary, they are easy to create and extremely cost effective.
Planes have remained fairly the same around the verse, although new propulsion and power engines have increased their range and speed. The fastest models, called ballistic planes, are shot at high velocity by magnetic mass drivers. While incredibly fast, even inertia screening does not make them comfortable and they often require repair between flights.
Fighter Jets are rather rare as planets rarely have aerial combat needs in atmosphere. Bombers and other support roles have largely been taken over by Space and Atmosphere able craft or simply done from orbit with long range weapons.
Are not quite like normal fighter, designed to be in space at all time, they are not aerodynamic and are equipped to accomplish feats that are impossible in gravity or atmosphere, such as 180 turns in place. They are powered by fusion engine and carry similar payload as larger ships. They however lack autonomy and range and thus are meant to be attached to other ships. Tonnage is between 20 to 100 tons.
Walkers are massive (twenty to eighty ton) vehicle that are composed of a cockpit and engine chassis attached to a pair of pneumatic legs, on the side of which weapons or tools are attached. They remain fairly light for their size due to their light weight material and construction techniques which use foamed metals as the main structure.
Although they are sometimes considered robots, they are only humanoid by the most cursory glance, not having heads and most times true arms to speak off.
They have become popular for combat in uneven terrain and urban warfare as they can more easily maneuver obstacles and debris, lighter models are also equipped with jump engines. As well as the intimidation factor as even light models tower over tanks and similar combat vehicles.