Rockets are the primary propulsion of spacecraft in modern times. They are suitable for short-range spaceflight, but for traveling to other solar systems, warp drive or hyperdrive is much more suitable, as it would take a rocket ship thousands or perhaps millions of years to travel such interstellar distances.
On the planet Krypton, rockets are a common part of transportation. They are used as propulsion for automobiles such as for their groundcars and aircars. They presumably make it possible to drive cars much faster than any Earth automobile. Nevertheless, one would assume that this is a much more restrained rocket, as it would be dangerous to drive at the high speeds a rocket-powered spaceship flies at.
Although space travel was illegal on Krypton, Kryptonian spacecraft also have rocket engines. One such craft was illegally launched from Krypton just prior to its' destruction. It contained Jor-El's son, Kal-El, who landed on Earth in Smallville, Kansas and grew up to become Superman.