The Hyperdrive is not directly a propulsion system, but is rather an accelerator that propels an already moving starcraft to exponentially faster speeds (thousand times the speed of light). When thus accelerated, travel between adjacent planets in the same solar system can be reduced to as little as a few minutes. Travel between adjacent solar systems requires anywhere between a few hours and a day, making the creation of small interstellar governments rather easy. While any vessel can include a hyperdrive, the hyperdrive is limited to a range of roughly 1 light year every 6 hours.
Hyper Drives are most common among species that are either new to the galactic scene or technologically backwards, and are quickly replaced by Jump Drives when possible.