There’s plenty of characters who turn into space vehicles that other characters fit inside to be transported around in, but not many that actually have their bodies crewed by others. Fortress Maximus as he appeared in the Headmasters animated series was the first one who came to mind; his bridge was regularly manned by the Autobot Headmasters.
Also, IDW’s given us the Titans, living city-starships. There’ve been a lot of those guys, but their starshipping days are behind most of them, as those that are known to still exist almost all settled on other planets which their crews colonized. The Titan Carcer is probably the most notable example of one who didn’t settle on a world and carried on being a spaceship up to the present day, captained by Elita One. But see this week’s Till All Are One #8 for more on him!