There are as many different Mass schedules as there are Churches (lots of those): We usually attend Mass in Barajas (pueblo, on the Plaza) at either 9:00 or 11:00 AM. On September 16 (Saturday) we found a Mass at Santa Catalina Church (Alameda de Osuna) at 6:30 PM. Most of the other Churches we looked at had later Saturday evening Masses.
Sunday AM we were leaving and they announced a Mass in the Chapel at Barajas airport for 12 noon.