I arrive from the US in T4S and my connecting flight is out of T4. Is 1.5 hours enough time? Do I have to do customs? Immigration? Pick up bags and transfer them?
That is enough time. You will not have to pick up the bag if your flights are one ticket;. when you check in the bag, you will see the final airport listed on the claim check. You will go through immigration where they stamp the passport.
Thank you so much!
I think you have enough time. Madrid is a big airport with lots of long walks to get anywhere.