Most airports have one terminal. Madrid-Barajas Airport (MAD) has two, and confusing them will cost you. On paper, the airport has five terminals: T1, T2, T3, T4, and T4S. In practice, there are two completely separate airport complexes sitting roughly 3 kilometers apart. The first is the older T1/T2/T3 cluster, connected on foot, functional, and noticeably dated. The second is …