Karen,

Re: Air Nostrum( regional partner of Iberia)

I just flew it from Madrid to Santander( a city in the north of Madrid). It was a smallish jet but seats were leather and very comfortable( much better than regular coach and another airline). I was surprised because this was barely an hour flight and they gave us breakfast! Also newspapers.

Be aware though that Air Nostrum also flies propeller planes. When I reserved my flight I made sure that it was in one of their jet flights.
If you have your flight number you could go to the Iberia website and check what kind of plane it is.