This ship hits 1200 Km/sec and survives the trip. You will reach a planet in about 10 secs.
Highly impractical, but its a prototype where the idea could be applied somewhere else. This ship design makes use of the following ideas.
- There is a height limit above, but no actual limit building downwards and sideways
- Engines look like they can't be stacked, but their no-build zone isn't actually that long
- Speed of a ship is primarily affected by width and other factors barely dent speed.
- Landmine reactive armor allows you to uncap your travel speed. (to a certain extent!)
Video of the ship in action: https://www.reddit.com/r/factorio/comments/1gkxgdq/1200_kmsec_ship/