Today, May 3 at 3pm, starts to operate the line 8 extension to Airport T4. So, the line will be Nuevos Ministerios/.../Aeropuerto T1-T2-T3/Barajas/Aeropuerto T4. The old Aeropuerto station changes its denomination to Aeropuerto T1-T2-T3.

And it carries a fare change: now there is an "Airport Supplement" (1 EUR) required for both airport stations users not using a Monthly/Yearly Pass. That "Airport Supplement" can be purchased at any Metro selling machine or at the selling machines located before the exit turnstiles at both airport stations if you have arrived there without it. There will also be "Single-tickets-with-the-supplement-included" (1+1=2 EUR) available at any Metro selling machine.

Edit: I forgot to mention that the Tourist Passes also work as the Monthly/Yearly Passes, so no supplement required when using one of these.