According to my sources three airlines operate their own equipment between Malaga(AGP) and Madrid(MAD)
Iberia (IB)- with MD80/757-200/A320/A321
Spanair(JK)- With MD80s
Air Europa(UX)- With 737-800s
I have flown it once. MAD-AGP was an IB 757 and I slept the entire flight as I had just flown to MAD from ORD. Returning AGP-MAD was an Airbus320. The service was better than IB's longhaul which really sucks. But on the other hand it was only 30 minutes. Also we encountered the most turbulence I have ever seen. Very bumpy, but the scenery you pass over is beautiful.