Twice a year I make return trips across Spain and use the A23 (Zaragoza - Valencia). Approaching the Teruel junction one has a good view of a large, modern airfield seemingly in the middle of nowhere. It has been interesting to note the increase in the number of large and mid-sized passenger aircraft on the pans, yet I've never seen any sign of movements. Anyway, I have finally got around to trying to satisfy my slight curiosity and came across
this link, which provides the answer - an airfield dedicated to maintenance & storage.