Just until recently, Ouarzazate Airport OZZ was only receiving international flights coming from Paris, France.
A few months ago, the famous low cost airline Ryanair open new flights to a few destinations in Morocco, and Ouarzazate was fortunately one of those chosen cities.
Madrid to Ouarzazate and Ouarzazate to Madrid by airplane has never been so easy. Most tickets are for sale at about 10 Euros one way, but if you search, you can also find ticket prices as low as 5 Euros one way, or 10 Euros round trip.