Direct daily flights to Madrid are available from major cities in the world. Madrid Barajas airport is about 30 min by car to the city center and most hotels.
Madrid airport is just 20-30 min underground (metro) ride to the city center. You should take line 8, which takes you directly to Nuevos Ministerios station, which is very close to the Madrid School of Mines (500 metres). From this station of the preceeding of postceeding ones you can change to other underground lines.