Actually, there's another option that combines metro and commuter train and it's faster and more suitable carrying big luggage that metro only, because both the Metro L8 and the Cercanias trains have places to fit the bags. And at Mendez Alvaro, if the metro station is UNDER the bus station, the train station is just OVER it
The trip would be this way:
- Metro line 8 from Airport to Nuevos Ministerios (12 min., trains every 5 minutes)
- Transfer to Cercanias Renfe (the commuter train system). Both Cercanias and Metro even share a platform separated by turnstiles, so the transfer is pretty easy.
- Take any train of the C7 or C10 lines Southbound to Mendez Alvaro (12 min., trains every 15 minutes)
Total cost of the trip: 1.35 EUR for a single trip Metro ticket plus 1.00 EUR for a single Cercanias ticket.