So where is São Sebastião? São Sebastião is two blue-line stops away from Marquês de Pombal and four from Restauradores. Restauradores is the metro stop that has access to the Rossio train station - which is the end station of the Sintra railroad.
The red line has a connection with the green line - so you can also change to a metro that takes you to Cais do Sodré - the end station for the Cascais train line.
The red line also passes in Oriente - where the trains to elsewhere in Portugal leave from. And yes, sometimes there are trains even to Sintra.
So this new metro extension for sure helps the access to the airport from Lisbon. And it is also interesting for those coming to Sintra, since the new train line Sintra/Azambuja was opened recently.
This is how you can now travel between Sintra a…