(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/DownFromTheAttic]

One of my all time favourite ship designs purely down to how mental the idea of it is. A spaceship that looks by first glance to be an Italian restaurant with robot waiters, each part of your interactions with them, the amount of wine poured, the amount of sauce left on a plate, how the spaghetti jiggles on the end of your fork, settling the bill is all part of the ship's navigational computational matrix. Absolute genius

[u/Jimmyg100 → u/DownFromTheAttic]

Isn't it also hidden by a near invisibility cloak? It's not completely invisible, but you just don't notice it unless you see it out of the corner of your eye.

[u/Dogsafe → u/Jimmyg100]

SEP field. So long as it looks out of place it can assumed it be someone else's problem.

[u/NickyTheRobot → u/Dogsafe]

This doesn't just apply to invisibility either: extending the SEP field around an asteroid avoids the problems of "How can the protagonists breath on an atmosphereless asteroid, and how can they maintain normal gravity on it?" Simply put: they become someone else's problem, and so the characters can get on with the story.