TheAssassin's Creed Odyssey's Kassandra and Valhalla's Eivor, they haven’t quite gotten to space yet. Clearly, since gamers have yet to see a spaceship in an Assassin’s Creed game, plans changed.
The plot of Assassin’s Creed certainly grew as the series went on. What started as a somewhat simple tale of an assassin taking out dangerous politicians and leaders quickly grew to involve mind-controlling relics and mystical precursor beings. Gamers who initially signed up for a time and globe-trotting adventure soon got much more than that: a complicated tale spanning millennia and drawing heavy inspiration from the once-prophesied end of the world scenario in 2012. While the end of the world obviously didn’t happen, the games have continued to build upon that foundation and Assassin's Creed's mysterious precursors as the backdrop for each new assassin’s experience. However, had things gone the way they were planned, the ending of the series would have come pretty early, and it would have sent Assassin’s Creed out with a bang.
Eurogamer has put out an article detailing just what that end would’ve looked like, and it involves a spaceship. A report from scholar Lars de Wildt discusses interviews he conducted with the original creator of Assassin’s Creed and the Creative Director of Assassin’s Creed 3 in which they explained that Assassin’s Creed 3 was supposed to end with Desmond and Lucy fleeing a dying Earth in a spaceship to start a new species elsewhere. Desmond would have taken out Abstergo once and for all, and then he and Lucy would have become a new Adam and Even on a new world.
Obviously, that’s not how things went, and by the time Assassin’s Creed 3 released, the ending did not involve even a glimpse of a spaceship, and Lucy was killed off. Abstergo remains in the series as a continual antagonist. It’s possible that there may still be a sort of Adam and Eve connection between the original Assassin's Creed protagonist Desmond and later protagonist Layla, but there still has been no sign of a spaceship. Whether or not that will happen in the future is anyone’s guess, though if it’s being openly discussed, it doesn’t seem likely.
The Assassin’s Creed franchise is still going strong, and shows no signs of slowing down. While gamers may not have gotten to see a spaceship in Assassin’s Creed 3 as originally planned, there’s no telling if that plotline will pop up in the series sometime in the future. At this point, given how fantastical the franchise's story beats have become, anything is possible.
Source: Eurogamer