Where did Superman get the adult-version of the spaceship that took him to and from the remains of Krypton?
Superman used the Kryptonian crystal technology in his Fortress of Solitude to build/grow the spaceship, much as Jor-El would have done when originally sending his infant son to Earth. It’s shown how Jor-El did this in the “Superman Returns Prequel: Krypton to Earth” comic book. It’s also worth noting that Lex Luthor (after learning everything from his time in the Fortress of Solitude) relates to Kitty that the Kryptonian crystal technology is capable of being used to create weapons and vehicles.
