The A1 is one of the "Aerobuses" connecting BCN airport to Barcelona city centre. Nothing to do with Sitges, that's in the opposite direction!
To get to Sitges from BCN aiport you can take the Mon-Bus from Terminal 1 to Sitges. They stop in Sitges centre (Av. Vilanova) that should be a 5-10 min walk to your hotel (in the seafront)
Be the first to rate this answer!