Madrid to Tangier or Marrakesh.

Very strong recommendation to skip Tangier, and head for Marrakech. Marrakech is the real thing, Tangier not so much.

Flights to Marrakech from Madrid and other cities in Spain (and in fact, across many major cities in western Europe) are often dirt cheap. Use skyscanner.com or whichbudget.com to search for low cost airlines on these routes. Note than many low cost flights do not go every day (often 2X or 3X a week), so be sure to search across multiple dates to find the cheap fares.

In many ways, you can think of Morocco as "the Mexico of western Europe". The parallel is surprisingly appropriate. Morocco provides low cost labor (some of it undocumented), fun-in-the-sun destinations, cheap vacations, beaches, rich exotic cultural and culinary contributions to western Europe. Although being there will feel like a real exotic adventure (because it is), in the major tourist areas, visiting Morocco will be a lot easier than you might expect at first. There will be plenty of European tourists there. But it's Africa, an Islamic country, developing world, with all the interesting rough edges that provides. It's a wonderful place to visit.

If you can manage even a little French, that will help (French, as badly spoken as yours, is the second language of Morocco, so helpful for official things). Have fun!

We were going to hit Tangier from southern Spain back in 2002, taking a ferry to Tangier and back. At the time Rick Steves described it as the “Tijuana of Morocco,” a relatively exotic, yet somewhat sleazy change of pace from the rest of a Spain trip. We wound up going to Portugal as part of that Spain trip, instead. My understanding is that Tangier has been somewhat cleaned up and is now a more sophisticated, less hustle-tourists-for-their-money destination, but haven’t gone there, even now. If you’re not already a short ferry ride from Tangier, and would be flying from Madrid, Marrakech would be just as easy to reach.

And exactly a year ago, January 2019, we were in Marrakech, on a 3-week Morocco trip. We flew from Denver to Marrakech, connecting thru London Heathrow airport. We took an all-day spice market/cooking class, and stayed at the wonderful Dar Kawa riad. After several days/nights, we flew to Fes and its higher, cooler setting, and its proximity to more ancient places. Our lodging in both Marrakech and Fes organized guides for us, to show fascinating sights and also protect us from hustlers.

We then had a weeklong desert tour, and came back to Marrakech for a couple more days before returning home. A big, historic city with an ancient medina old town, Marrakech is the one place to go, if you’re going only one place in Morocco. Fes is a close number two. Again, haven’t been to Tangier, but from what I’ve learned, it wouldn’t beat either Marrakech or Fes as a must-see destination. Unless it was a lot more convenient and cheaper, there’d be no reason for someone to consider Tangier.

If you are going to spend several nights in Morocco, the obvious places are Marrakesh and Fez. You may be limited by flights. I don't think there are daily flights to either city. Where else in Spain are you going to be?

When I chose a tour to Morocco, I looked at a lot of 2-week guided tour itineraries and absolutely none of them went to Tangier - not even the one I took which stayed overnight in a town only 60 km away. That should tell you all you need to know.

Great advice so far, SKIP TANGIER and list Marrakesh or Fes.

My understanding is that Tangier has been somewhat cleaned up and is now a more sophisticated, less hustle-tourists-for-their-money destination

I went last year and if what I saw was a cleaned up, more sophisticated and less hustle-tourists-for-their-money destination then I dread to think what it was like before. The place is a dump and offers little of interest, go to Marrakesh instead.