How to get to Salamanca
Unfortunately the airport of Salamanca Matacán has no commercial flights. Only spanish Iberia, via its subsidiary AirNostrum, flies to Salamanca from Barcelona.
The most common way to arrive to Salamanca is then to land in Madrid or in Valladolid.
Madrid: Barajas Airport.
It is connected with all major European airports.Madrid Barajas is also served by low cost airlines like Ryanair (ryanair.com) and EasyJet (easyjet.com).
Salamanca Bus Express Service
There is a Barajas - Salamanca bus express service; it takes you directly from Barajas airport to Salamanca in 2 hours and 45 minutes. The bus leaves from Terminal 1.
Bus tickets are available online (http://www.salamancabarajas.com/), or at the El Corte Inglés travel agency (T1, 1st floor). Otherwise you can buy tickets on board the bus. You can save money with the return ticket (in spanish Ida y Vuelta; if you do not know with which bus will return, you can ask an "open" return, Vuelta abierta).
If no bus corresponds to you arrival, then you will have to go to the Méndez Alvaro South Bus Station (Estación de Autobuses Sur, Calle Méndez Alvaro). Madrid's Barajas Airport has Metro stations in Terminal T2 and the newer Terminal T4 (for more details http://www.metromadrid.es/). Take line 8 from airport to Nuevos Ministerios and then line 6 (circular line) from Nuevos Ministerios to Méndez Álvaro. You can also go directly by TAXI. But better not to accept offers from taxi drivers inside the airport building.
Get by Train
Another option is to take the train to Salamanca from Chamartín Train Station. Take line 8 from Barajas airport to Nuevos Ministerios and then line 1 to Chamartín. The Spanish train company is Renfe www.renfe.es
Valladolid: Villanubla Airport
The main airline here is Ryanair. When you exit the baggage claim area, you will find Ryanair desk at the opposite side, all on the left. There you buy a ticket for Linecar, the service to Valladolid bus station (there are also taxis that charge a fixed rate). Once there, go to the Avanzabus desk and buy a ticket for Salamanca (1 hour 30 minutes). If you're lucky there might be a direct bus from Villanuebla to Salamanca that corresponds to check-in and boarding times of Ryanair, check on avanzabus.com. You can save money with the return ticket (in spanish Ida y Vuelta; if you do not know with which bus will return, you can ask an "open" return, Vuelta abierta). The bus station and the train station in Valladolid are 3 minutes apart by foot.