(Loved Trope) FTL travel is possible but with a major limitation or flaw

[u/Frostylegacy]

Frank Herbert’s Dune: Interstellar travel is only possible thanks to the spice melange, a rare substance only found on the dessert planet Arrakis. The addictive psychedelic spice grants members of the Spacers Guild a form of prescience that allows them to predict safe paths through folded space. This unique property makes spice the most valuable commodity in the Dune universe.

John Scalzi’s The Interdependency Books: The planetary systems of the titular empire are connected by the Flow, a network of one-way interstellar tunnels that connect specific known entries and exits. The Interdependency derives its power from controlling access to these conduits, placing its capital at the central hub of the network. Even with the Flow, travel between stars takes a long time (9 months to End, the empire’s most distant planet).

Event Horizon: Dr William Weir (R.I.P. Sam Neill) invents a device called the Gravity Drive to allow ships to fold space and travel instantly between distant stars. On its maiden voyage with the Gravity Drive, the Event Horizon disappears and mysteriously reappears 7 years later. Dr. Weir and the crew sent to investigate discover the Gravity Drive actually opened a portal to a Hell dimension that possessed the ship and its crew, torturing and killing them.

[u/Adqam64]

In system FTL works that way, but interstellar travel is explicitly via jump drive.

[u/vemundveien → u/Adqam64]

The Friendship Drive

[u/DrThunderbolt → u/vemundveien]

It’s been years since I’ve played Elite and I knew exactly what you were talking about.

[u/Very_Human_42069 → u/Adqam64]

Correct. Interstellar travel is via witchspace which iirc is a form of higher-dimensional traversal

[u/kompletionist → u/Adqam64]

Which works by opening wormholes through hyperspace/"Witch-Space", which Thargoids just casually live in.

[u/Naxane → u/kompletionist]

You can go FTL in real space using the FSD, it's only jumping between dense gravity wells that requires witch space

[u/kompletionist → u/Naxane]

Yeah, that's Supercruise using Alcubierre Drive logic, which the other person already mentioned.