Carlos's place was exactly what I was looking for: clean, simple and comfortable stay as close to the airport as possible. It was a 3 minute metro ride and a 5 minute Uber ride. Still, I went afterall to the centre and it was only 35 minutes via metro. Carlos was a great host. He was kind and ready to help with any questions I had about the flat or Madrid. The neighborhood was very quiet, safe and residential. I'd recommend his place for any solo traveler needing a convenient place to stay close to the airport.