From BCN as mentioned above the Rodalies (Cercanías) goes from BCN T2 (and it's a bit of a walk from the terminal building to the station) to Barna Sants and not T1, but Sants to Zaragoza is a much shorter journey than Madrid Atocha or Chamartín to Zaragoza. You'd have the same issue with a terminal change at MAD anyway unless you landed at T4(S), since that's where the airport train station is, but at least the station is actually within the terminal building.