When preparing to write a science fiction novel, I had to choose between ways for my characters to travel between worlds. This is, I believe, critical to deciding even before writing. So as food for thought, here are some of the ways speculative fiction writers can handle interstellar travel in their works.
1. Warp drive – Perhaps mostfamously thanks to the Star Trek and Star Wars series, space ships able to travel faster than light can flit between the planets in a matter of hours. While convenient for moving the plot, Einstein had some things to say about speeds faster than light. But hey, it’s fiction.
2. Cryogenic sleep – In the Alien movies starring Sigourney Weaver, the characters remain in a deep sleep as their ships travel at realistic speeds. Sometimes hundreds of years pass before the ships’ computer awakens them and the action commences.
3. Star gates – In fiction using star gates, such as the Stargate movies and television series, a wormhole or portal of some kind allows instantaneous travel across vast distances of space. In my own novel, man made gates orbit around planets, allowing relatively easy travel between worlds, although it still takes a couple weeks to get a space ship out to the gates. A recent Tech Times article discussing the movie Interstellar notes this mode of travel may indeed be possible.
There are other methods of moving characters around, teleportation between planets for instance. But, these three seem to me to be the most common methods.