"Cid (シド Shido) is a character who appears, or is at least mentioned, in all Final Fantasy installments since Final Fantasy II. Although he is rarely the same age, and never the same individual in each of the main series, he is usually presented as an owner, creator, and/or pilot of airships and provides transportation to the main characters and their party members at various points of the game. In the second game, he has a friendly relationship with a woman named Hilda; he also has a close relationship with a woman of the same name in the ninth and eleventh installments.
Cid does not appear in the original Nintendo Entertainment System version of Final Fantasy, but he is retroactively inserted in subsequent versions (from Final Fantasy Origins onwards), where he is mentioned as the creator of the party's airship. "
Source: Wikipedia, "Cid_(Final_Fantasy)", available under the CC-BY-SA License.