When non-Kalsan shuttles travel at near lightspeed (99% of the speed of light), time passes slower for the shuttle crew than those left behind on the planet. Velocities are relative. So, you need to compare lightspeed to something else.

If a shuttle left for a planet 4.3 light years away, it would take about 8 and half years. For the crew, only a little over a year would pass. For the crew, the planet would only be about .6 light years away or about 19 days each way. This difference in time is called time dilation and it is a measured phenomenon.

The formula to calculate lightspeed travel is 2 * Light Years / .99 = Planet Years.

Kalsan shuttles can take advantage of "bends" or "holes" in space to shorten the distance travelled. This is called Faster-Than-the-Speed-of-Light (FTSL) travel. The shuttles do not actually break the speed of light, but shorten the distance travelled. Although the Kalsan carefully guard the secrets of these techniques, it is known that they take advantage of the Fundamental Laws of Nature to "step through" dimensions in a fraction of the time.