Given the events of last week, I’m not sure spotting at MAD is a good idea right now – the Spanish were at one time rather anti- and its only been the last couple of years or so no one has gotten any hassle.

Anyhow, to answer the question as best I can… BA use T4S which is the mid-field dock associated with the new terminal. All the non-shengen flights using T4 seem to go to the mid-field dock. As befits any new terminal arrivals are segregated from departures. It may (repeat may) be possible, if you already have a boarding card for your return leg, to just go immediately through transfers in the mid-field dock and up into the departure level – this level yields good views of several of the runways. If that doesn’t work, you will have no choice but to get onto the underground train and go to the main T4 terminal, where you will have to clear immigration. Landside, the new T4 did not seem to yield any good views of the entire airfield, and therefore once landside I suspect a trip to the infamous cafe in T2 (or to the mound in Barajas if you have time and want better photos) may be in order – again, lingering outside T4 near the parking deck (which won’t yield many good views anyway) may be inadvisable after last week’s events. The distance between the new T4 and the older terminals T1-T3 is NOT walkable – presumably there are transfer busses but I know nothing of their pick up and drop off locations or frequency.

When you can check in for your return flight, I recommend proceeding airside and again taking the train to the mid-field dock T4S (bear in mind that the recommended time from passport control to some of the mid-field gates is 22 minutes anyway!). Again, from the mid-field dock, a lot of the movements will be visible albeit through glass.

Andy